Amazon.com (ISBN 0471252867, Hardcover)

Carl Sagan may have been one of the greatest scientists who ever lived. Then again, he may have been a relentless self-promoter who convinced everyone he was one of the greatest scientists who ever lived. Keay Davidson, science writer for the San Francisco Chronicle, aims to explain this complicated man in his biography. One thing is clear: Sagan was an extremely difficult man to love, a scientist whose passion for astronomy and biology was unparalleled, but who had little ability to express basic emotions to his wives and children. Davidson looks for reasons for this emotional distance in Sagan's childhood, when his relationship with his mother was intense and sometimes difficult. She encouraged her bright young son to be an "intellectual omnivore," to be passionate about knowledge, but she didn't give him the tools to relate to humans as individuals.

As his stellar science career developed, Sagan built a reputation as a leftist who believed that "science could serve liberal ideals," and as an arrogant man with an unshakable confidence in his own brain. Davidson writes that Sagan developed his famous skepticism as an undergraduate. Sagan suffered from a "troubling mix of intense emotion and stark rationalism," writes Davidson. He succeeded (mostly) in balancing passion with reason, a balance that made him a perfect popularizer of science, a trustworthy authority who preached that an open mind was the most valuable scientific tool. Davidson was influenced personally by Sagan's writings, and he sometimes works a little too hard at puncturing the myths surrounding Sagan, but this biography is one that deserves to be read by Sagan's fans and detractors alike. It's a compelling, very real assessment of an all-too-human god of science. --Therese Littleton