Evolution: The First Four Billion Years, edited by Michael Ruse and Joseph Travis is an authoritative and comprehensive summary of our current understanding of evolution. It also covers the history and philosophy of evolution and the interaction between evolutionary study, and religion and society. You can download an excerpt here .
Steve Jones is one of the best writers on evolution and Darwin going around, and his latest book won't disappoint his legion of fans. Darwin's Island looks at the huge amount of work Darwin performed at his home in Down House on topics as different as dogs, barnacles, insect-eating plants, orchids, earthworms, apes and human emotion.
Darwin had the help of many people in creating his "revolution", and three of the most important were Alfred Wallace, T H Huxley and Joseph Hooker. These three and Darwin himself are the subject of Darwin's Armada: How Four Voyagers to Australasia Won the Battle for Evolution and Changed the World by Iain McCalman.
The Cambridge Companion to the Origin of Species, edited by Michael Ruse and Robert Richards contains 18 essays on everything from "the origin" of the Origin to the rhetoric of the Origin and its impact on political theory and philosophy. You can read the table of contents here and an excerpt here.