This Atlas is not what it should be. If fate had been kinder, each of the four planetary bodies represented here would have had its own Atlas, each larger than this volume. Don't blame the author, though; the culprit is an elegant yet critical device called the HGA, explained in Chapter 1.3. Should you pass over this book on your way to the used “pilates-at-home” bookshelf or toss it in the recycle paper bin? I hope not. Despite its shortcomings, this Atlas is the most complete representation we will have of the surfaces of Jupiter's large Galilean satellites for the next decade, objects that should be called planets, regardless of anyone's peculiar definition of that term.

Complex in detail and beautiful in a universe of wonders, the Galilean satellites fill the eye and mind in equal measure. They are also of considerable historical importance. My place in their history begins in 1972, the year I entered high school. A notice in the Buffalo Evening News announced the hiring of a manager to lead a new Mariner mission to the outer planets and their moons. At the time, these worlds were little more than dusky points of light. The Voyager mission, as it came to be called, was in reality a poor-cousin replacement for the Grand Tour, an ambitious plan to tour the entire Outer Solar System with a fleet of spacecraft.