The last decade has seen an exponential growth in the number of Internet users, and networks rely on high performance storage devices for server and database applications. This handbook reviews advanced signal processing, modulation, coding techniques, and architectures for recording read channels. It is divided into four major areas that cover theoretical background, state-of-the-art read channels and their subsystems, the treatment of the data channel, and modulation and error control coding. The text also reviews read channel technology including novel read channel architecture such as post processor, super chip, and issues of digital design, chip testing, and manufacturing.