This document began life as a quick intro to Lisp-Stat for our book on Geophysical Inverse Theory (a draft of which is available from Samizdat). It expanded last fall when JS taught Object-Oriented Programming to a group of sophomore engineering students at Colorado School of Mines. Lisp-Stat is an Object-Oriented flavor of Lisp that is extremely easy to learn. It puts you in a position to benefit from OO design more quickly than C++, for example. In addition, it has powerful statistical and numerical features that make it a very useful tool for interactive scientific calculations.