Richard A. Muller of UC Berkeley is an engaging, smart, and maverick physicist who has spent a good part of his career chewing on off-beat but not crazy hypotheses until they either fall apart or gain some credibility. He is good at being realistic about those that don't hold up or stall for lack of more data (his hunch never caught on that a distant solar companion, a brown dwarf named Nemesis, occasionally sprays comets into the inner solar system). Perhaps by nature he looked fishy-eyed at global warming science until he took a hard look for himself. Two tempting ways to judge his latest analysis of climate change data are 1) Wow, if even a skeptic of the mainstream's consensus that climate change has us ankle deep in offal with knee- and hip-deep in sight can change his mind, that's a triumph for scientific method and maybe a politically effective tide-turner or, 2) He's a scientist. He had not paid much attention to global warming before. He and...