This book covers the fundamental concepts, historical background, theoretical foundations, solution methodologies, computational algorithms, and engineering applications of contact micromechanics. It presents a unified computational framework built upon the theories of eigenstrains and contact mechanics, designed to investigate the contact behavior of engineering materials across a wide range of industrial applications. Detailed discussions are provided on the mathematical formulations of physical contact problems and the development of computational methods—particularly those based on the fast Fourier transform (FFT)—along with multi-field solution strategies. In addition, alternative mechanics approaches for addressing similar problems are presented for comparison and broader knowledge extension. This book serves as a valuable resource for engineers and researchers, offering both a solid foundation for learning and a platform for practical application and innovation.