Successful application of Ansys Chemkin to engineering and chemistry problems requires some basic understanding of the theory and formulations behind chemically reacting flow simulations. The Chemkin Theory Manual provides a broad overview of the relationships and formulations used in calculations of chemical property and source terms. It also provides brief derivations and explanations of the governing equations solved by Chemkin Reactor Models, as well as a discussion of numerical solution techniques and sensitivity analysis employed in the models. In most cases these descriptions contain references to more rigorous treatments of the theoretical background that are available in the open literature. For further background information, we recommend a textbook written by several of Chemkin’s original authors: Chemically Reacting Flow: Theory and Practice. [1]