An omnibus book. The first chapter is a lot of fun because it motivates the subject well from both a pure and applied standpoint -- these are problems that are both interesting in their own right and useful. And with the material covered, it's sort of amazing how much we can do in the field -- there's so much that goes into solving the most fundamental questions, like localizing a robot.
The sources that I recognized at the end of chapters were generally good, so I feel comfortable drawing recommendations for further reading from the sources I didn't.