Adventures in Celestial Mechanics, Second Edition is written as a textbook, apparently for undergraduates, though this is never specifically stated. The book is engaging and surprisingly easy to read; I recommend it to anyone who wants just a bit of background in celestial mechanics or a brief introduction before plunging into graduate-level texts.
The book's strength lies in its historical and heuristic introduction of the various fundamental concepts of celestial mechanics in easy-to-follow detail. Such concepts include Kepler's laws of motion as a consequence of Newton's law of gravitation, the solution of Kepler's equation, and the rocket equation. Kepler's equation, which relates the position in an orbit at a given time, is annoying in that it can only be solved iteratively in the direction one usually wants to go (where in the orbit is the body at time t). Many of the greatest minds in physics and astronomy have searched for compact, quickly-converging, or just plain understandable solutions to this problem. Feynman's recently made famous “lost lecture” was his second attempt to present a comprehensible derivation of Kepler's equation to Caltech freshmen. I was subjected to the first version when I was a freshman and can attest that it needed a second try. At least I did.