“Handbook of Mathematical Functions with Formulas, Graphs, and Mathematical Tables” by Milton Abramowitz and Irene A. Stegun. Students and professionals in the fields of mathematics, physics, engineering, and economics will find this reference work invaluable. A classic resource for working with special functions, standard trig, and exponential logarithmic definitions and extensions, it features 29 sets of tables, some to as high as 20 places.