The tiny planets Mercury and Pluto represent opposite extremes of the solar system. Mercury is the closet planet to the Sun, which looms over its scorched surface three times larger than it does in Earth's sky, while frozen Pluto lies in the comet-haunted darkness at the solar system's most distant frontier--so far away that the Sun appears as little more than another bright star. Yet both planets, as different as they are, hold important clues to the origin of the solar system. The Worlds Beyond series visits bodies in space, from their formation billions of years ago to the present day. Using the most up-to-date knowledge of space science and observational data, Ron Miller explores the evolution, composition, and landscape--including NASA photos, original diagrams, and striking illustrations. Publishing two titles per season; other title this season is SATURN, with MARS and ASTEROIDS, COMETS, AND METEORS to follow in spring 2004.