diff --git a/.idea/pytools.iml b/.idea/pytools.iml
index f5c7f766..a8c82518 100644
--- a/.idea/pytools.iml
+++ b/.idea/pytools.iml
@@ -16,7 +16,7 @@
       <excludeFolder url="file://$MODULE_DIR$/docs" />
       <excludeFolder url="file://$MODULE_DIR$/.mypy_cache" />
     </content>
-    <orderEntry type="jdk" jdkName="facet-base" jdkType="Python SDK" />
+    <orderEntry type="jdk" jdkName="pytools-develop" jdkType="Python SDK" />
     <orderEntry type="sourceFolder" forTests="false" />
   </component>
   <component name="PackageRequirementsSettings">
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index cfb4ef8b..75e7c27c 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -50,6 +50,6 @@ repos:
         language_version: python310
         pass_filenames: false
         additional_dependencies:
-          - numpy~=1.24
+          - numpy~=2.0
           - pytest
           - packaging
diff --git a/RELEASE_NOTES.rst b/RELEASE_NOTES.rst
index b487cdf3..de391330 100644
--- a/RELEASE_NOTES.rst
+++ b/RELEASE_NOTES.rst
@@ -11,6 +11,14 @@ Release Notes
 *pytools* 3.0 adds support for language features introduced up to and including
 Python 3.10, and drops support for Python versions.
 
+*pytools* 3.0.2
+~~~~~~~~~~~~~~~
+
+- BUILD: :mod:`numpy` |nbsp| 2 is now supported
+- FIX: :func:`.issubclass_generic` now supports unions, tuples of types, and ``None``,
+  and uses clearer error messages if called with invalid arguments
+
+
 *pytools* 3.0.1
 ~~~~~~~~~~~~~~~
 
diff --git a/azure-pipelines.yml b/azure-pipelines.yml
index e1b6aaa8..939c73cf 100644
--- a/azure-pipelines.yml
+++ b/azure-pipelines.yml
@@ -89,7 +89,7 @@ stages:
           - script: |
               # package dependencies for mypy
               dependencies=(
-                numpy~=1.24
+                numpy~=2.0
                 packaging
                 pytest
               )
diff --git a/environment.yml b/environment.yml
index ae2a1280..317b5466 100644
--- a/environment.yml
+++ b/environment.yml
@@ -5,7 +5,7 @@ dependencies:
   # run
   - joblib            ~= 1.2
   - matplotlib        ~= 3.6
-  - numpy             ~= 1.24
+  - numpy             ~= 2.0
   - pandas            ~= 2.0
   - python            ~= 3.10.14
   - scipy             ~= 1.10
diff --git a/pyproject.toml b/pyproject.toml
index 8e7ad8b5..7dd5ad8d 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -16,7 +16,7 @@ license = "Apache Software License v2.0"
 requires = [
     "joblib            ~=1.0",
     "matplotlib        ~=3.6",
-    "numpy             >=1.23,<2a", # cannot use ~= due to conda bug
+    "numpy             >=1.23,<3a", # cannot use ~= due to conda bug
     "pandas            >=1.5",
     "scipy             ~=1.9",
     "typing_inspect    ~=0.7",
@@ -80,7 +80,7 @@ typing_extensions = "~=4.0.0"
 # maximum requirements of gamma-pytools
 joblib = "~=1.3"
 matplotlib = "~=3.8"
-numpy = ">=1.26,<2a"  # cannot use ~= due to conda bug
+numpy = ">=2,<3a"  # cannot use ~= due to conda bug
 pandas = "~=2.0"
 python = ">=3.12,<4a"   # cannot use ~= due to conda bug
 scipy = "~=1.12"
diff --git a/src/pytools/__init__.py b/src/pytools/__init__.py
index 819356e4..b96059f0 100644
--- a/src/pytools/__init__.py
+++ b/src/pytools/__init__.py
@@ -2,4 +2,4 @@
 A collection of Python extensions and tools used in BCG GAMMA's open-source libraries.
 """
 
-__version__ = "3.0.1"
+__version__ = "3.0.2"
diff --git a/src/pytools/data/_linkage.py b/src/pytools/data/_linkage.py
index eca40d96..163ed7e5 100644
--- a/src/pytools/data/_linkage.py
+++ b/src/pytools/data/_linkage.py
@@ -32,7 +32,7 @@
 # Type variables
 #
 
-LinkageMatrix = npt.NDArray[np.float_]
+LinkageMatrix = npt.NDArray[np.float64]
 
 
 #
diff --git a/src/pytools/data/_matrix.py b/src/pytools/data/_matrix.py
index c01c1b21..ff5250bf 100644
--- a/src/pytools/data/_matrix.py
+++ b/src/pytools/data/_matrix.py
@@ -32,7 +32,7 @@
 #
 
 T_Matrix = TypeVar("T_Matrix", bound="Matrix[Any]")
-T_Number = TypeVar("T_Number", bound="np.number[npt.NBitBase]")
+T_Number = TypeVar("T_Number", bound="np.number[Any]")
 
 #
 # Ensure all symbols introduced below are included in __all__
@@ -59,7 +59,7 @@ class Matrix(HasExpressionRepr, Generic[T_Number]):
     names: tuple[npt.NDArray[Any] | None, npt.NDArray[Any] | None]
 
     #: the weights of the rows and columns
-    weights: tuple[npt.NDArray[np.float_] | None, npt.NDArray[np.float_] | None]
+    weights: tuple[npt.NDArray[np.float64] | None, npt.NDArray[np.float64] | None]
 
     #: the labels for the row and column axes
     name_labels: tuple[str | None, str | None]
@@ -155,8 +155,8 @@ def _arg_to_array(
         else:
 
             def _ensure_positive(
-                w: npt.NDArray[np.float_] | None, axis: int
-            ) -> npt.NDArray[np.float_] | None:
+                w: npt.NDArray[np.float64] | None, axis: int
+            ) -> npt.NDArray[np.float64] | None:
                 if w is not None and (w < 0).any():
                     raise ValueError(
                         f"arg weights[{axis}] should be all positive, "
@@ -352,7 +352,7 @@ def _message(error: str) -> str:
 
 
 def _top_items_mask(
-    weights: npt.NDArray[np.float_] | None,
+    weights: npt.NDArray[np.float64] | None,
     current_size: int,
     target_size: tuple[int | None, float | None],
 ) -> npt.NDArray[np.bool_]:
@@ -385,7 +385,7 @@ def _top_items_mask(
         # THe target weight is expressed as a ratio of total weight
         # (0 < target_ratio <= 1).
 
-        weights_sorted_cumsum: npt.NDArray[np.float_] = weights[
+        weights_sorted_cumsum: npt.NDArray[np.float64] = weights[
             ix_weights_descending_stable
         ].cumsum()
         mask[
@@ -401,12 +401,12 @@ def _top_items_mask(
 
 def _resize_rows(
     values: npt.NDArray[T_Number],
-    weights: npt.NDArray[np.float_] | None,
+    weights: npt.NDArray[np.float64] | None,
     names: npt.NDArray[Any] | None,
     current_size: int,
     target_size: tuple[int | None, float | None],
 ) -> tuple[
-    npt.NDArray[T_Number], npt.NDArray[np.float_] | None, npt.NDArray[Any] | None
+    npt.NDArray[T_Number], npt.NDArray[np.float64] | None, npt.NDArray[Any] | None
 ]:
     mask = _top_items_mask(
         weights=weights, current_size=current_size, target_size=target_size
diff --git a/src/pytools/typing/_typing.py b/src/pytools/typing/_typing.py
index f989289b..479a153c 100644
--- a/src/pytools/typing/_typing.py
+++ b/src/pytools/typing/_typing.py
@@ -26,7 +26,7 @@
     Sequence,
     ValuesView,
 )
-from types import GenericAlias
+from types import GenericAlias, NoneType, UnionType
 from typing import (
     AbstractSet,
     Any,
@@ -373,13 +373,13 @@ def get_type_arguments(obj: Any, base: type) -> list[tuple[type, ...]]:
     return list(map(get_args, get_generic_instance(ti.get_generic_type(obj), base)))
 
 
-def issubclass_generic(subclass: type | Never, base: type | Never) -> bool:
+def issubclass_generic(subclass: Any, base: Any) -> bool:
     """
     Check if a class is a subclass of a generic instance, i.e., it is a subclass of the
     generic class, and has compatible type arguments.
 
-    :param subclass: the class to check
-    :param base: the generic class to check against
+    :param subclass: the (potentially generic) subclass to check
+    :param base: the (potentially generic) base class to check against
     :return: ``True`` if the class is a subclass of the generic instance, ``False``
         otherwise
     """
@@ -396,16 +396,56 @@ def issubclass_generic(subclass: type | Never, base: type | Never) -> bool:
     elif base is Never:
         return False
 
+    # Special case: if the subclass is a union type, check if all types in the union are
+    # subclasses of the base class
+    if get_origin(subclass) in (typing.Union, UnionType):
+        return all(issubclass_generic(arg, base) for arg in get_args(subclass))
+
+    # Special case: if the base class is a union type, check if the subclass is a
+    # subclass of at least one of the types in the union
+    if get_origin(base) in (typing.Union, UnionType):
+        return any(issubclass_generic(subclass, arg) for arg in get_args(base))
+
+    # Special case: if the base class is a tuple, check if the subclass is a subclass of
+    # at least one type in the tuple
+    if isinstance(base, tuple):
+        try:
+            return any(issubclass_generic(subclass, arg) for arg in base)
+        except TypeError as e:
+            raise TypeError(
+                f"isinstance_generic() arg 2 must be a type, type-like, or tuple of "
+                f"types or type-likes, but got {base!r}"
+            ) from e
+
+    # Typehints can contain `None` as a shorthand for `NoneType`; replace it with the
+    # actual type
+    if subclass is None:
+        subclass = NoneType
+    if base is None:
+        base = NoneType
+
+    # Replace deprecated types in typing with their canonical replacements in
+    # collections.abc
     subclass = _replace_deprecated_type(subclass)
     base = _replace_deprecated_type(base)
 
     # Get the non-generic origin of the base class
     base_origin = get_origin(base) or base
+    if not isinstance(base_origin, type):
+        raise TypeError(
+            f"isinstance_generic() arg 2 must be a type, type-like, or tuple of types "
+            f"or type-likes, but got {base!r}"
+        )
 
     # If the non-generic origin of the subclass is not a subclass of the non-generic
     # origin of the base class, the subclass cannot be a subclass of the base class
     subclass_origin = get_origin(subclass) or subclass
-    if not issubclass(subclass_origin, base_origin):
+    if not isinstance(subclass_origin, type):
+        raise TypeError(
+            f"isinstance_generic() arg 1 must be a type or type-like, but got "
+            f"{subclass!r}"
+        )
+    elif not issubclass(subclass_origin, base_origin):
         return False
 
     # If the base class is not a generic class, there are no type arguments to check
@@ -567,7 +607,7 @@ def _get_origin_parameters(
         )
 
 
-def _replace_deprecated_type(tp: type) -> type:
+def _replace_deprecated_type(tp: T) -> T:
     """
     Replace deprecated types in :mod:`typing` with their canonical replacements in
     :mod:`collections.abc`.
@@ -577,18 +617,23 @@ def _replace_deprecated_type(tp: type) -> type:
         deprecated
     """
 
-    if tp.__module__ == "typing":
+    origin: type | None = get_origin(tp)
+    if (
         # Check if the same type is defined in collections.abc
-        origin: type | None = get_origin(tp)
-        if origin is not None and origin.__module__ == "collections.abc":
-            log.warning(
-                f"Type typing.{tp.__name__} is deprecated; "
-                f"please use {origin.__module__}.{origin.__name__} instead"
-            )
-            args: tuple[type, ...] = get_args(tp)
-            if args:
-                # If the type has arguments, apply the same arguments to the replacement
-                return cast(type, origin[args])  # type: ignore[index]
-            else:
-                return origin
+        origin is not None
+        and tp.__module__ == "typing"
+        and origin.__module__ == "collections.abc"
+    ):
+        log.warning(
+            "Type typing.%s is deprecated; please use %s.%s instead",
+            tp.__name__,  # type: ignore[attr-defined]
+            origin.__module__,
+            origin.__name__,
+        )
+        args: tuple[type, ...] = get_args(tp)
+        if args:
+            # If the type has arguments, apply the same arguments to the replacement
+            return cast(T, origin[args])  # type: ignore[index]
+        else:
+            return cast(T, origin)
     return tp
diff --git a/src/pytools/viz/_matplot.py b/src/pytools/viz/_matplot.py
index 9b14ccbe..8cefa669 100644
--- a/src/pytools/viz/_matplot.py
+++ b/src/pytools/viz/_matplot.py
@@ -304,13 +304,13 @@ def color_for_value(self, z: int | float) -> RgbaColor:
         pass
 
     @overload
-    def color_for_value(self, z: npt.NDArray[np.float_]) -> npt.NDArray[np.float_]:
+    def color_for_value(self, z: npt.NDArray[np.float64]) -> npt.NDArray[np.float64]:
         """[overload]"""
         pass
 
     def color_for_value(
-        self, z: int | float | npt.NDArray[np.float_]
-    ) -> RgbaColor | npt.NDArray[np.float_]:
+        self, z: int | float | npt.NDArray[np.float64]
+    ) -> RgbaColor | npt.NDArray[np.float64]:
         """
         Get the color(s) associated with the given value(s), based on the color map and
         normalization defined for this style.
diff --git a/src/pytools/viz/dendrogram/_style.py b/src/pytools/viz/dendrogram/_style.py
index 6e053bc7..a031ac61 100644
--- a/src/pytools/viz/dendrogram/_style.py
+++ b/src/pytools/viz/dendrogram/_style.py
@@ -222,7 +222,7 @@ def draw_leaf_labels(
 
     def _get_ytick_locations(
         self, *, weights: Sequence[float]
-    ) -> npt.NDArray[np.float_]:
+    ) -> npt.NDArray[np.float64]:
         """
         Get the tick locations for the y axis.
 
@@ -231,7 +231,7 @@ def _get_ytick_locations(
         """
         weights_array = np.array(weights)
         # noinspection PyTypeChecker
-        ytick_locations: npt.NDArray[np.float_] = -(
+        ytick_locations: npt.NDArray[np.float64] = -(
             np.arange(len(weights)) * self.padding
             + weights_array.cumsum()
             - weights_array / 2
diff --git a/src/pytools/viz/matrix/_matrix.py b/src/pytools/viz/matrix/_matrix.py
index bc1e02b9..308230d9 100644
--- a/src/pytools/viz/matrix/_matrix.py
+++ b/src/pytools/viz/matrix/_matrix.py
@@ -155,16 +155,16 @@ def draw_matrix(
             npt.NDArray[Any] | None,
         ],
         weights: tuple[
-            npt.NDArray[np.float_] | None,
-            npt.NDArray[np.float_] | None,
+            npt.NDArray[np.float64] | None,
+            npt.NDArray[np.float64] | None,
         ],
     ) -> None:
         """[see superclass]"""
         ax: Axes = self.ax
         colors = self.colors
 
-        weights_rows: npt.NDArray[np.float_]
-        weights_columns: npt.NDArray[np.float_]
+        weights_rows: npt.NDArray[np.float64]
+        weights_columns: npt.NDArray[np.float64]
         # replace undefined weights with all ones
         weights_rows, weights_columns = tuple(
             np.ones(n) if w is None else w for w, n in zip(weights, data.shape)
@@ -172,8 +172,8 @@ def draw_matrix(
 
         # calculate the horizontal and vertical matrix cell bounds based on the
         # cumulative sums of the axis weights; default all weights to 1 if not defined
-        column_bounds: npt.NDArray[np.float_]
-        row_bounds: npt.NDArray[np.float_]
+        column_bounds: npt.NDArray[np.float64]
+        row_bounds: npt.NDArray[np.float64]
 
         row_bounds = -np.array([0, *weights_rows]).cumsum()
         column_bounds = np.array([0, *weights_columns]).cumsum()
@@ -200,7 +200,7 @@ def draw_matrix(
         # draw the matrix cells
         for c, (x0, x1) in enumerate(zip(column_bounds, column_bounds[1:])):
             for r, (y1, y0) in enumerate(zip(row_bounds, row_bounds[1:])):
-                color: npt.NDArray[np.float_] = cell_colors[r, c]
+                color: npt.NDArray[np.float64] = cell_colors[r, c]
                 ax.add_patch(
                     Rectangle(
                         (
@@ -224,7 +224,7 @@ def draw_matrix(
         y_tick_locations = (row_bounds[:-1] + row_bounds[1:]) / 2
 
         def _set_ticks(
-            tick_locations: npt.NDArray[np.float_],
+            tick_locations: npt.NDArray[np.float64],
             tick_labels: npt.NDArray[Any],
             axis: Axis,
             tick_params: dict[str, Any],
@@ -461,15 +461,15 @@ def draw_matrix(
             npt.NDArray[Any] | None,
         ],
         weights: tuple[
-            npt.NDArray[np.float_] | None,
-            npt.NDArray[np.float_] | None,
+            npt.NDArray[np.float64] | None,
+            npt.NDArray[np.float64] | None,
         ],
     ) -> None:
         """[see superclass]"""
 
         def _axis_marks(
             axis_names: npt.NDArray[Any] | None,
-            axis_weights: npt.NDArray[np.float_] | None,
+            axis_weights: npt.NDArray[np.float64] | None,
         ) -> Iterable[str] | None:
             axis_names_iter: Iterable[Any]
 
diff --git a/src/pytools/viz/matrix/base/_base.py b/src/pytools/viz/matrix/base/_base.py
index 5b4dc4c8..d0c52ac0 100644
--- a/src/pytools/viz/matrix/base/_base.py
+++ b/src/pytools/viz/matrix/base/_base.py
@@ -67,8 +67,8 @@ def draw_matrix(
             npt.NDArray[Any] | None,
         ],
         weights: tuple[
-            npt.NDArray[np.float_] | None,
-            npt.NDArray[np.float_] | None,
+            npt.NDArray[np.float64] | None,
+            npt.NDArray[np.float64] | None,
         ],
     ) -> None:
         """
diff --git a/test/test/pytools/test_typing.py b/test/test/pytools/test_typing.py
index 8788cd02..e9f29661 100644
--- a/test/test/pytools/test_typing.py
+++ b/test/test/pytools/test_typing.py
@@ -11,6 +11,7 @@
 from typing import Any, Generic, TypeVar
 
 import pytest
+from typing_extensions import Never
 
 from pytools.typing import get_generic_instance, issubclass_generic
 
@@ -106,6 +107,43 @@ def test_issubclass_generic() -> None:
         AsyncIterator_typing[Mapping[str, int]], AsyncIterable[Mapping[str, Any]]
     )
 
+    assert issubclass_generic(int, float | int)
+    assert issubclass_generic(float, float | int)
+    assert issubclass_generic(int | float, float | int)
+    assert issubclass_generic(int | float, typing.Union[float | int])
+
+    assert issubclass_generic(int, (float, int))
+
+    assert issubclass_generic(Never, None)
+    assert issubclass_generic(None, None)
+    assert not issubclass_generic(None, int)
+
+    with pytest.raises(
+        TypeError,
+        match=(
+            r"^isinstance_generic\(\) arg 2 must be a type, type-like, or tuple of "
+            r"types or type-likes, but got 3$"
+        ),
+    ):
+        issubclass_generic(int, 3)
+
+    with pytest.raises(
+        TypeError,
+        match=(
+            r"^isinstance_generic\(\) arg 2 must be a type, type-like, or tuple of "
+            r"types or type-likes, but got \(3, <class 'int'>\)$"
+        ),
+    ):
+        issubclass_generic(int, (3, int))
+
+    with pytest.raises(
+        TypeError,
+        match=(
+            r"^isinstance_generic\(\) arg 1 must be a type or type-like, but got 3$"
+        ),
+    ):
+        issubclass_generic(3, int)
+
 
 def test_get_generic_instance() -> None:
 
diff --git a/test/test/pytools/viz/dendrogram/test_dendrogram.py b/test/test/pytools/viz/dendrogram/test_dendrogram.py
index 476c4144..b9b09ba0 100644
--- a/test/test/pytools/viz/dendrogram/test_dendrogram.py
+++ b/test/test/pytools/viz/dendrogram/test_dendrogram.py
@@ -25,7 +25,7 @@ def linkage_matrix() -> npt.NDArray[np.int_]:
 
 
 @pytest.fixture
-def linkage_tree(linkage_matrix: npt.NDArray[np.float_]) -> LinkageTree:
+def linkage_tree(linkage_matrix: npt.NDArray[np.float64]) -> LinkageTree:
     """Create a linkage tree for drawing tests."""
     return LinkageTree(
         scipy_linkage_matrix=linkage_matrix,
@@ -34,7 +34,7 @@ def linkage_tree(linkage_matrix: npt.NDArray[np.float_]) -> LinkageTree:
     )
 
 
-def test_dendrogram_drawer_text(linkage_matrix: npt.NDArray[np.float_]) -> None:
+def test_dendrogram_drawer_text(linkage_matrix: npt.NDArray[np.float64]) -> None:
     leaf_names = list("ABCDEFGH")
     leaf_weights = [(w + 1) / 36 for w in range(8)]