This important monograph is the first comprehensive compendium of engineering models used in high-speed penetration mechanics. The book consists of two parts. The first part (more than a quarter of the book's content) is in fact a handbook giving a very detailed summary of the engineering models used for the analysis of high-speed penetration of rigid projectiles into various media (concrete, metals, geological media). The second part of the book demonstrates the possibilities and efficiency of using approximate models for investigating traditional and nontraditional problems of penetration mechanics. Different chapters in the books are devoted to different classes of problems and can be read independently. Each chapter is self-contained, which includes a comprehensive literature survey of the topic, and carries a list of used notations. The bibliography includes more than 700 references. This monograph is a reliable and indispensable reference guide for anyone interested in using engineering models in high-speed penetration mechanics.