Numerical Python (often called NumPy) is a widely used extension library for fast operations on fixed-type arrays, of any dimensionality, in Python. Since the underlying code is well-optimized C, any speed limitations of Python's interpreter usually go away when major operations are performed in NumPy calls. As successful as NumPy has been, its developers have decided to supercede NumPy with a new module called Numarray that is mostly, but not quite entirely, compatible with NumPy. In this installment, the author looks both at the general features of NumPy and at the specific improvements forthcoming with Numarray.