Missing Links

by John Reader. Little, Brown, $19.95. As a photojournalist, Mr. Reader is able to take a reasonably nonpartisan view of the discoveries and theories of paleoanthropologists. He presents a brisk, sober history of the search for evidence of human origins, keeping a straight face even when describing the Piltdown hoax and those squabbles over terminology that scientists conduct as though their lives depended on victory. (Since financial support may depend on victory, a certain belligerence is understandable, for fossil-hunting is expensive.)