Quick-name a scientist!. Was your answer Carl Sagan? It probably was-no other person has brought so much science to the public. His loss to a rare disease four years ago left a void still unfilled by anyone else. His life in science and the workings of science itself are worthy of exploration by any educated person, and two biographies that have appeared over the last year serve that purpose well.
I sampled Carl's life through William Poundstone's Carl Sagan: A Life in the Cosmos (Henry Holt, 473 pages, paperback, $16) when it first appeared, just before the other book came to print. Having my appetite whetted, I purchased Davidson's book but let it sit on the shelf awhile-after all, how different could it be? How wrong I was!
Poundstone's book indeed introduces the reader to all of the details of his life, but with a somewhat detached viewpoint, a workman-like effort. This is reflected in the chapter breaks arranged by years and location. Keay Davidson's Carl Sagan: A Life (Wiley, 540 pages, paperback,$18), on the other hand, gets emotionally involved with the story of Sagan's life, and weaves some themes among the details-not quite judgmental, but observant. Davidson makes his logical breaks at Sagan's projects and ideas. While this makes for some jumps and repeats, these are forgiven for his more interesting overall flow. Both authors are science writers of some note, and not scientists themselves.
Read Poundstone for the science-it is complete and detailed. Particularly well done and relevant to recent NASA discoveries is the story of Carl's involvement in the Viking probes that looked for life on Mars in the 1970s. The disagreements on the choice of landing sites and the critical decisions on which experiments to repeat or change a bit between the limited number of runs reveal the tough choices that have to be made in science, often with insufficient information.
Davidson's forte', however, is the flare for interpreting Sagan's vibrant personality and his personal life as revealed through both his public presence and private affairs. The author spends more time on Carl's books (including Pulitzer-winning Dragons of Eden), TV works (popular visits on Johnny Carson and his PBS hit, "Cosmos"), and movie (Contact, featuring a performance by Jodie Foster that would have pleased him greatly had he lived to see the film's completion). Yet, Carl's entry into the public arena was not always looked favorably upon by his peers. His having been rejected for tenure at Harvard and blackballed for membership in the prestigious National Academy of Science are certainly partially attributable to his limelight activities. I suspect his colleagues, with their nose to the grindstone of their often boring sub-sub-specialties were secretly envious of this rising star and generalist of science. Here was a man who studied the stars, warned of nuclear winter, got arrested in a protest, developed a "best of Earth" album to affix to the starbound Voyager probe, and debunked pseudoscience. He appeared in NASA press conferences as comfortably as on the Tonight Show. Published articles in the Astrophysical Journal and in the Sunday supplement Parade magazine.
If you want a taste of how modern science operates, and of the personal hustle necessary for success, Poundstone's work covers the bases, and does so with more depth. Davidson appears to have more details with an extensive list of reference notes, but it is mostly in the form of quotations that are of low impact in the unfolding story. He also has an annoying habit born of the word processing age: familiar phrases, and other chunks of text that are repeated a bit too frequently to not be noticed.
For the person intrigued with the romance of science, and romance in general, Davidson's A Life is for you. Not to be sexist, but if women are truly from Venus and men from Mars (and Sagan made fundamental contributions to the study of both planets), the female readers would want to read Davidson and the men Poundstone. I'm not sure whether Carl would approve of this advice-while he was obviously a chauvinist at home, at least with his first two wives, he was a promoter of female scientists at work!
If you read them both, I would read Poundstone first, for the science. With that as a basis you can allow your self to be immersed in the personality developments presented by Davidson. In either book you will find rewarding reading about a man sorely missed by those of us who appreciate both doing good science and bringing it to the public.