"High Sierra," a 1941 Humphrey Bogart thriller, "isn't a great film," movie historian David Thomson writes in his slim new "Bogie" biography, but it was part of "a new moment in American history" -- one of the first films that made it OK to pull for the villains.

Everybody knows that moviegoers often identify with characters operating on the far end of the law, but Thomson is one of the few writers who can (or would even try to) tell us almost exactly when this trend began.

The author of many books about movies, including his exhaustive "The New Biographical Dictionary of Film," Thomson has written four mini-bios of actors whose careers flourished in the first half of the 20th century. His subjects -- Bogart, Ingrid Bergman, Gary Cooper and Bette Davis -- are the pilot members of this "Great Stars" book series. Obvious choices, sure, but these short books are jaunty distillations of extraordinary lives and screen careers.

The books are informal in tone, and not particularly revelatory. Still, they combine astute artistic and cultural assessments with gossipy tidbits in a useful and breezy manner. Thomson notes that Cooper was at once hugely successful and one-dimensional for this simple reason: "No one ever asked him to play a bad guy." He writes smartly about the onscreen defiance that marked Davis' best roles. And he says that Hemingway told Bergman that she needed shorter hair to play the female lead in "For Whom the Bell Tolls."

Think of these books as a literary answer to the DVD's commentary track -- not necessary to enjoy the films, but helpful information for the curious.

KEVIN CANFIELD