Books: Brain Matter

THE DRAGONS OF EDEN by CARL SAGAN 263 pages. Random House.

Like squids, scientists protect themselves with clouds of impenetrable ink. Not Carl Sagan. His jargon-free book The Cosmic Connection (1973) involved thousands of readers in the search for life beyond earth. Last year, during the Mars probe, he became a TV celebrity with plausible descriptions of the creatures that might be populating outer space. The Dragons of Eden should involve thousands more in the exploration of inner space — the human brain.

Sagan, 42, occupant of a chair in astronomy at Cornell University, is...