The Equator software was conceived as an integral part of the book An Atlas of Functions , Second Edition, though its utility is not limited to users of the book. The Atlas is available in both print and electronic formats and full details can be found at www.springer.com. Equator is offered for sale as a stand-alone unit in part to benefit those whose access to the Atla s is through a portal to the electronic version. Equator is a software package designed to generate numerical values of over 200 mathematical functions used by engineers, scientists and others. Among the functions made available by Equator are such simple ones as cosines and binomial coefficients, as well as more elaborate examples such as Bessel functions and elliptic integrals. In addition to its primary goal of providing function values, Equator will perform a number of subsidiary tasks. Equator is easy to use and its operation will soon become as intuitive as using your hand calculator.