This newest edition of Principles of Lithography reflects the continuing advancement of lithographic technology. In recent years, certain topics, such as line-edge roughness (LER), multi-electron-beam writers, and nonlinear overlay models, have become much more significant to practicing lithographers, and more extensive treatments are therefore provided. EUV lithography is on the threshold for use in high-volume manufacturing, at nodes where a number of complex phenomena are relevant, and the chapter on EUV lithography has been expanded accordingly. New references and homework problems have been added. It is expected that the reader of this book will have a foundation in basic physics and chemistry. No topics will require knowledge of mathematics beyond elementary calculus.