Book excerpt: This volume provides a broad overview of the fundamental materials science of thin films that use silicon as an active substrate or passive template, with an emphasis on opportunities and challenges for practical applications in electronics and photonics. It covers three materials classes on silicon: Semiconductors such as undoped and doped Si and SiGe, SiC, GaN, and III-V arsenides and phosphides; dielectrics including silicon nitride and high-k, low-k, and electro-optically active oxides; and metals, in particular silicide alloys. The impact of film growth and integration on physical, electrical, and optical properties, and ultimately device performance, is highlighted.