While conducting experimental observations to analyze the damage mechanisms and failure modes, the author develops micromechanical damage models and constitutive models to predict the first matrix cracking stress, multiple matrix cracking density, matrix crack opening displacement, and cracking closure stress at high temperatures. The effects of composite’s constituent properties, stress level, and ambient temperature on matrix cracking, opening, and closure are also discussed. This book will help material scientists and engineering designers to understand and master the matrix cracking and closure behavior of fiber-reinforced CMCs.