This is a recent addition to the Tab/McGraw-Hill lineup on how to use an AVR microcontroller. The AVR datasheets are fine, but they're not as useful as this book!
The Programming & Customizing the PICmicro book is a book for beginners and features 12 project and 30 experiments.
Mechanical Devices for the Electronic Experimenter covers numerous mechanisms for robotics and electronics applications. A great resource for brainstorming!
This essential title in McGraw-Hill's ROBOT DNA SERIES is just what robotics hobbyists need to build an effective drive train and gain a full understanding of robot locomotion.
Gordon McComb's Robot Builders Bonanza - 4th Ed. is considered by many to be the bible of hobby robotics.
123 Robotics Experiments for the Evil Genius by Myke Predko is a great starting point for anyone who is just interested in either electronics or robotics.
This book walks you through the essential skills you need to build and control devices using the Propeller chip and its parallel processing environment.
Microcontrol'n Apps is an intermediate book on PICmicros.
Time'n & Count'n is an intermediate level book for PICmicro users that focuses on timers and counters.