OXFORD, England —You walk out of a soft-falling rain into the living room of an Oxford don, with great walls of books, handsome art and, on the far side of the room, graceful windows onto a luxuriant garden.

Does this man, arguably the world’s most influential evolutionary biologist, spend most of his time here or in the field? Prof. Richard Dawkins smiles faintly. He did not find fame spending dusty days picking at shale in search of ancient trilobites. Nor has he traipsed the African bush charting the sex life of wildebeests.

He gets little charge from such exertions.

“My interest in biology was pretty much always on the philosophical side,” he says, listing the essential questions that drive him. “Why do we exist, why are we here, what is it all about?”

It is in no fashion to diminish Professor Dawkins, a youthful 70, to say that his greatest accomplishment has come as a profoundly original thinker, synthesizer and writer. His epiphanies follow on the heels of long sessions of reading and thought, and a bit of procrastination. He is an elegant stylist with a taste for metaphor. And he has a knack, a predisposition even, for assailing orthodoxy.