It was last year in Philadelphia, during a breakfast meeting with Kevin Lynch and our publisher David Tranah, that the idea of a second edition of our Modern Robotics textbook was floated by David. Memories of the agony of completing the first edition by now having receded, and not yet fully grasping what we might be getting ourselves into, Kevin and I actually began going through the list of chapters, musing about what chapters could remain as is, what chapters needed update, and what new chapters might be added.