The Z-80 Microcomputer Handbook

This book met my two requirements for a Z80 book -- usefulness, and availability at a good price. Using this book as my primary reference source, I have been able to put together a working Z80 computer. Definitely recommended; while not as complete a guide to the instruction set as "Programming the Z80" is, this book provides a good mix of hardware and software information, along with examples on how to connect the various control lines essential to correct operation. If you're working with Z80 hardware, this book will help.