As a lecture series this must have been exciting; as a book it presents a few difficulties. The nine contributors (distinguished astronomers, astrochemists and astrophysicists) survey the major features of our solar system with varied concessions to a lay audience. The reader with a dim science background will have to keep realigning the different approaches to put overlappings and apparent contradictions into perspective. Aside from this, there's plenty to stir the imagination. Perhaps the most accessible chapter is Carl Sagan's account of the planets--whose chemical composition, changing according to their proximity to the sun, is the key to the conditions under which they were created. Sagan suggests that the ""seasonal"" alterations in the surface of Mars, attributed by some to vegetation, may actually be the result of dust blown by the planet's fierce winds. A. G. W. Cameron goes over some of the same territory in a chapter on the formation of the solar system (his own preferred hypothesis is that the present system was created from a solar nebula twice the mass of the present sun, the originally innermost planet being our moon). Matching the moon's geophysical features with the composition of the retrieved moon rocks, John A. Wood concludes that the cooling process of the moon was marked by an epoch of surface congealing followed by two separate upsurges of hotter material, resulting in three major types of component rock. Myron Lecar suggests that the asteroids (which were thought to be the debris of a shattered planet when we were in school) may actually be pieces of the primeval matter out of which the other inner planets eventually agglomerated. There are other sections on comets, planetary atmospheres, the sun (whose corona, at a temperature of 2,000,000 K, is so rarefied that a man would freeze to death in it). Dense but challenging.