These days, science and philosophy don’t seem to be the best of friends. Some prominent scientists dismiss philosophers as chasing vague concepts into “murky and inconsequential” rabbit holes, as the physicist Steven Weinberg once put it. And philosophers accuse scientists of imperial overreach in their attempts to claim ultimate authority on questions like consciousness, free will and the existence of God.

But in “Brave Genius,” Sean B. Carroll tells the interlocking stories of a philosopher and a scientist, Albert Camus and Jacques Monod, who were not just passionate friends but sometimes seemed to be living two versions of the same life. Both were active in the French Resistance during World War II, and after the war both devoted themselves to fighting the intellectual corrosions of Communist ideology. Both men won the Nobel Prize, Camus for literature and Monod for physiology, in recognition of fundamental discoveries about the regulation of gene expression.

And the similarities run even deeper. Both Camus and Monod, Dr. Carroll writes, were concerned with the same fundamental problem: how to act morally, even heroically, in a random, indifferent universe.

Camus, whose 100th birthday is being commemorated this year in France, will be the marquee attraction for many readers. Dr. Carroll, a molecular biologist, occasional contributor to Science Times and onetime college French major, tells his story crisply if somewhat dutifully — from Camus’s early days as a journalist through his first literary success with “The Stranger,” his rise to global fame and his premature death in a car crash in 1960, at age 46.