Electronics

Practical Electronics for Inventors, Paul Scherz
The Art of Electronics, Paul Horowitz

Algorithms

The Algorithm Design Manual, Steven Skien
Algorithms, Robert Sedgewick and Kevin Wayne
Grokking Algorithms, Aditya Bhargava

Artifical Intelligence

Artificial Intelligence: A Modern Approach, Stuart Russell and Peter Norvig

Robotics

Principles of Robot Motion, Howie Choset
Modern Robotics: Mechanics, Planning, and Control, Kevin Lynch
Introduction to Autonomous Mobile Robots, Roland Siegwart
Planning Algorithms, Steven M. La Valle
Robot Motion Planning, Jean-Claude Latombe