A Field Guide to Stars and Planets
If I had to choose a small number of books to take with me into exile on some deserted island somewhere, this would definitely be one of them (and offhand I'm not sure I can name any others).
An entire astronomy library packed into a single portable field guide, Jay Pasachoff's entry in the Peterson Field Guide series is a delightful introduction to, and reference for, the universe revealed in the night sky.
If you have any interest in astronomy at all, you can always find something in here to look at or just to sit and ponder about.
Besides the obvious things like monthly star charts for both northern and southern hemispheres, the book contains a complete 52 chart atlas of the sky put together by Wil Tirion with notes on objects in each chart, clever finder charts and tables for the planets for a ten year period, history and lore of the naming of the constallations, many, many photographs of astronomical objects taken by Hubble and other telescopes, an atlas of the moon, and many enlightening charts and tables of things like details of the brightest/nearest stars, the planets and their moons, and so on.
There's a section on each of the planets, and of course lots of coverage of the sun and eclipses of the sun and moon.
It always surprises me that this book doesn't seem to get as much respect in astronomical circles as I think it deserves. While you can certainly fill a library with astronomical books and atlases that are better than this field guide in any one area, you will not do better than this book in stuffing all of that information together in one "to go" package.A Field Guide To Stars And Planets
is an excellent gift for a child starting to get interested in science and the world at large.