Evolution
Following up his cosmicManifold series,  Stephen Baxter peers back on a more prosaic history in the worthy yet  unevenEvolution. The book is nothing less than a novelization of  human evolution, a mega-Michener treatment of 65 million years starring  a host of smart, furry primates representingHomo sapiens's  ancestry. Each stage of our ancestry is represented by a character of  progressively increasing intelligence, empathy, and brain size, who must  survive predation and other perils long enough to keep the  natural-selection ball rolling. While Baxter carefully follows some widely  accepted theories of evolution--punctuated equilibrium, for instance--he  also strays from the known in postulating air whales and sentient,  tool-wielding dinosaurs. And why not? There's nothing in the fossil  record to contradict his musings about those things, or about the first  instances of mammalian altruism and deception, which he also lets us  observe. From little Purga, a shrewlike mammal scurrying under the feet  of ankylosaurs, all the way through Ultimate, the last human descendant,  Baxter adds drama and a strong story arc to our past and future. But he  spends too much time on details of the various prehumans' lives, which  can become repetitive: fight, mate, die, ad infinitum. And  readers eager for a science-fictional adventure will only find  satisfaction in the posthuman chapters at the end. Despite these flaws,Evolutiongrips the attention with an epoch-spanning tale of the  random changes that rule our genetic heritage. Recommended.--Therese  Littleton