Most books discuss the theory and computational procedures of finite elements (FE). In the past this was necessary, but today's software packages make FE accessible to users who knows nothing to the theory or of how FE works. People are now using FE software packages as "black boxes', without knowing the dangers of poor modeling, the need to verify that results are reasonable, or that worthless results can be convincingly displayed. Therefore, it is important to understand the physics of the problem, how elements behave, the assumptions and restrictions of FE implementations, and the need to assess the correctness of computed results.