The advent of inexpensive, high-performance computers and new efficient
algorithms have made possible the automatic recognition of numerically
computed constants. In other words, techniques now exist for
determining, within certain limits, whether a computed real or complex
number can be written as a simple expression involving the classical
constants of mathematics. These techniques will be illustrated by
discussing the authors' work in recognizing Euler sums and in finding
new formulas for $\pi, \pi^2 and \log^2{(2)}$, formulae that permit
digits to be extracted from their expansions.