Famous mathematical constants include the ratio of circular circumference to diameter, pi=3.14 ..., and the natural logarithmic base, e=2.178 ... Students and professionals usually can name at most a few others, but there are many more buried in the literature and awaiting discovery. How do such constants arise, and why are they important? Here Steven Finch provides 136 essays, each devoted to a mathematical constant or a class of constants, from...