Molecular simulation opens the door to very simple (if tedious) answers to many fundamental questions. By judiciously analyzing the trends with experimental data and model equations, we can gain a fundamental understanding of molecular interactions and the meaning of terms like ideal gas, density, temperature, pressure, energy, repulsive, attractive, and adiabatic. These terms are often used without a thorough understanding of their meaning and implications. A proper understanding is the key to perceiving the connections between various subjects like power generation, refrigeration, distillation, and extraction. Even anomalies like unimolecular reactions and transport phenomena like diffusion seem like straightforward observations in the context of molecular simulation. Having established the conceptual basis through molecular simulation, the reduction to practice through model equations and fitting to experimental data can follow a systematic evolution from the molecular scale to the global scale that should seem less mysterious. This process of systematic analysis and refinement is essential to the engineering perspective. Equal significance should be recognized for the results derived here and the process by which they were derived. The ultimate goal is to help you formulate your own questions and strategies for answering those questions.