Kim Stanley Robinson writes good, didactic, socially conscious hard science fiction. He's best known for his Mars trilogy and The Years of Rice and Salt, which imagined what would have happened if Europe hadn't come out of the plague. Forty Signs of Rain, just out in paperback, is the first in a planned near-future global warming trilogy. Lots of well-developed characters, plenty of science and Beltway intrigue, and a big old flood. Good, relevant end-of summer fare, especially after Hurricane Katrina.