Understanding the oxidation and pyrolysis chemistry of hydrocarbons can aid in developing thermal conversion processes and in improving combustion applications. Optimization of engine performance requires an understanding of how a fuel's molecular structure affects important combustion properties. The course presents the current state-of-the-art in comprehensive chemical kinetic modeling for gas-phase and liquid- phase reacting flows. The course will cover the development of large databases of chemical reaction pathways with associated kinetic rate parameters, as well as thermochemical and transport properties for all reactant, intermediate, and product species. First, the mapping out of detailed reaction pathways at the temperatures and pressures relevant to chemical reactors and combustion applications will be discussed. Next the art of assigning rate constants using chemical intuition and quantum chemical modeling will be covered. The determination of thermochemical and transport properties is achieved using both molecular modeling tools and empirical methods. The comprehensive models are then validated against data from well-defined experimental configurations using zero- dimensional and one-dimensional reacting flows whose physics can be simulated exactly. These models are finally employed to determine the thermal degradation and oxidation pathways relevant to the prediction of combustion performance in practical applications.