While serving in the U.S. Congress, Abraham Lincoln, a self-taught learner, mastered Euclid's Elements (Basler 1953). Most students today do not study mathematics for recreation. Unlike Lincoln, they need a little help in learning how to write a geometry proof. Today's technology--specifically, The Geometer's Sketchpad[R] (GSP)--can help make learning to write proof easier and more exciting. The practice of proof writing is one of the most challenging subjects to teach in the secondary school mathematics curriculum and in the mathematics education curriculum for preservice teachers. Many students consider themselves good at mathematics because they are good at learning the procedures needed to solve problems. However, these same students may balk at solving a word problem or writing a proof. Such aversion is due largely to the fact that no general algorithm exists that tells a student how to approach and write a proof. For this reason, the subject is difficult to teach. In this article, the author outlines her approach to teaching geometry to secondary school preservice teachers, a method that can be applied to a high school geometry class as well. GSP can be used as a construction tool as well as a medium for discovery and conjecture. Although there is no simple step-by-step process for writing proofs, modern technology can aid in writing geometry proofs in a way that the traditional compass and straightedge never could. (Contains 6 figures.)