This is the book that first demonstrated to me the power of evolutionary psychology to help us understand ourselves. Published a year before Robert Wright's The Moral Animal, which covers much of the same territory, this is to my mind a more sophisticated and more direct exposition. Both books are characterized by a sly wit and an incisive expression, but Ridley meanders less among the relics of Freud and Darwin and is less concerned about whether we're moral or not and more concerned with what's sexy and why. He had a lot of fun with this book and it shows.
The "red queen" is a metaphor for an arms race. In an arms race both sides run as fast and as hard as they can to stay in the same place relatively speaking. In evolution the arms race is between parasite and host or between predator and prey. Both are running as fast as they can just to keep up, because when one gets an advantage, the other finds a counter. The red queen comes from Lewis Carroll's Through the Looking Glass and What Alice Found There (1871) since that monarch ran as fast as she could but never got anywhere at all. The red queen is also a metaphor for the theory that there is no "progress" in evolution, that "...species do not get better at surviving... Their chances of extinction are random" (p. 64).
Ridley covers a lot of territory here, ranging from sex to the handicap principle to gossip to why our brains are big (to figure out what the other person is up to!). The Red Queen answers the question, "Why is there sex?" Apparently we have sexuality rather than asexuality because of the arms race between microbes and our immune systems. Sex is a way of storing defenses against parasites in the gene pool of the species and then mixing them anew each generation to fool the microbes. Without the gene pool and the DNA mixing, the microbes would quickly evolve a way around the organism's defenses; but with sexuality the organism juggles its "locks" every generation and so is able to keep up with the fast-mutating microbes. When again the microbes evolve the keys to these locks, the gene pool is mixed again and the organism comes up with an old lock that the microbes again have to evolve a key to.
Some of the fun is the incisive way Ridley presents the ideas, and the ideas he chooses to present. For example, note how effectively he demolishes Freud's naive incest taboo theory on pages 282-286. Also interesting is his presentation of the idea that it is not thinness in women per se that attracts men, but a low ratio of waistline to hip line that fetches them. There are chapters entitled "Polygamy and the Nature of Men," and "Monogamy and the Nature of Women." In Chapter 9, "The Uses of Beauty," Ridley goes into some detail on why men prefer thin and blond women. And on pages 217-218 he explains why women cuckold their mates: "This is because her husband is, almost by definition, usually not the best male there is-else how would he have ended up married to her?" She wants the parental care of her husband and some other man's superior-she thinks-genes.
Ridley is rather modest and says that most of the ideas in the book are not his and at any rate many of them will undoubtedly be proven wrong. This is refreshing to read when I think about all the delusive ideas so proudly trumpeted by popular books on evolution and human behavior in the past. Desmond Morris's The Naked Ape (1967) and Elaine Morgan's The Aquatic Ape: A Theory of Human Evolution (1982) come to mind, both fine books, but now seen to be substantially mistaken.
Written in an engaging and lucid style, The Red Queen really is the best of a number of books on evolutionary psychology to appear over the last decade and one that is a delight to read.