Knopf

"You're good," detective Sam Spade tells the treacherous Brigid O'Shaughnessy early in the film The Maltese Falcon. "It's chiefly your eyes, I think, and that throb you get in your voice when you say things like 'Be generous, Mr. Spade.'"

It was something in Humphrey Bogart's eyes, and the flat bemusement in his voice that made those lines so good, of course. In his new biography of Bogart, Tough Without a Gun (out today in print and e-book from Knopf), Stefan Kanfer provides a deft, brief sketch of how Bogart learned to put those intangibles into a performance. But he gives short shrift to, and ultimately fails to answer, the more compelling question he poses in the book: How did an actor who was limited to embodying the particular stresses of America in depression and war become inimitable—and immortal?

Immortality is a difficult subject. The gods have never felt it particularly necessary to be comprehensible to mere mortals. And mere mortals who rise above their station don't necessarily understand how they got there, either. It doesn't actually make sense that Humphrey Bogart would endure as a romantic hero when the much handsomer, and much more sexually compelling Clark Gable is largely remembered for his performance in Gone With the Wind as Rhett Butler, a character who owes as much to his literary creator, Margaret Mitchell, as to Gable. Bogart's humor was much more bitter and clipped than William Powell's, whose performances as Nick Charles would seem to have held up better in an age that venerates irony than Bogart's bitten-off jokes. But that's part of what's fun about Bogart. There's something satisfying and superior about loving things that are out of fashion, where less observant people fail to see the merits.

Trying to explain the joys of the slightly irrational is an impossible task, but that doesn't mean that Kanfer doesn't produce some fun in trying. It's clear that Bogart was always going to be somewhat idiosyncratic. He was raised by a physician and a feminist illustrator; had a slightly turbulent Navy career but never saw action in World War II; at one point earned a poor living playing chess in New York; got his start on Broadway playing empty, rich young men, spending more time in theater than his peers; and kept a "F.Y. fund" rather than spending his early paychecks on upgrading himself to a Hollywood lifestyle.

And Kanfer does a nice job in explaining the gap in American movies that Bogart expanded to fill, first in the decidedly un-ethnic gangster pictures that first earned him steady movie work:

Bogart was something new on-screen. [Edward G.] Robinson (born Edward Emanuel Goldenberg) and [Paul] Muni were Jewish; [James] Cagney was half Irish, and that half dominated his appearance and style. The appeal of these men was ethnic; they represented the human sorrow of every city—immigrants, or the children of immigrants, who had taken a wrong turn. In contrast to those stars, Humphrey was a WASP....He represented the notorious malefactors from the heart of the heart of the country: 'Baby Face' Nelson, 'Pretty Boy' Floyd, John Dillinger, Bonnie Parker and Clyde Barrow, all of whom had been dramatically ands savagely hunted down and killed in 1934.

And then more generally in his movies about war and poverty, because "he became particularly adept at playing individuals under stress. Audiences, similarly afflicted, felt that he understood them and they made him a star." That doesn't explain why audiences continue to love Bogart so much though, particularly as Hollywood's shifted towards a cruder kind of aspirationalism in entertainment. Movies today are far more often about affirming that we'll all rise out of difficult circumstances than providing a sense of solidarity with the difficult circumstances that Americans are in now.

And Kanfer's book can't quite make the leap to explaining why Bogart endures. He alludes to the impact Beat the Devil—Bogart's Truman Capote-written caper parody had on the development of camp culture—but never draws direct lines between it and other movies, or explores the fascinating contradictions of a icon of dry masculinity contributing to the gayest of genres. Similarly, his descriptions of the Brattle Theater's accidental discovery of Bogart's drawing power, starting with its 1957 Casablanca screenings, is charming:

In 1964 Time sent a reporter to the Brattle, where the Bogart festival was now a hallowed tradition. A Blue Parrot room, named for Sydney Greenstret's cafe in Casablanca, had been set up in the theater. Nearby a jukebox kept playing 'As Time Goes By.' 'When Bogart lights a cigarette on the screen,' the article stated, 'girls respond with big, sexy sighs.' Asked about the object of their affection, a Radcliffe student lamented the Age of Analysis: 'Bogie is everything we wish Harvard men were,' she said. 'Bogie's direct and honest. He gets involved with his women but he doesn't go through an identity crisis every five minutes.'

But it's one thing to become part of an undergraduate tradition, and quite another to influence the way Americans watch old movies. Did those Brattle screenings become the linchpin of American repertory cinema? The whimsical treasure of this archival research suggests that Kanfer might have more productively spent his time exploring questions like that, rather than offering boilerplate summaries of various historical events where he has little to add.

Such boilerplates are particularly annoying towards the end of the book when Kanfer dips briefly into the debate over the demise of "real" men and grown-up movies in contemporary American cinema. He might have argued that the kind of masculinity Bogart represents is simply unreproducible (though there is always promise: Tom Hardy, the British actor vaunted to American stardom by his turn as a forger in Inception, looks like he could smack around a dame or two). But the argument wouldn't stand up against the obvious shift in the American experience that made Bogart's weariness less relatable, and in the economics of entertainment that put ticket-buying dollars in younger hands, something that Kanfer acknowledges.

Kanfer says at the beginning of the book that "impersonators don't 'do' Tobey Maguire or Brad Pitt or Leonardo DiCaprio or Christian Bale et al. because these actors don't have distinctive voices or faces." But is that shift truly because Bogart was a more distinctive man and actor than the craftsmen who followed him? Or is it because actors like Pitt, DiCaprio and Bale have a wider variety of roles available to them, and thus are less easily pigeonholed? Or because trends in acting have come to favor Method-like absorption in parts, a technique that Kanfer says Bogart disliked but nonetheless learned from and put to good use in The African Queen? Is Bogart simply the last man of his type that we value? Gods can end up being less relevant to our day-to-day existence than our flawed, vital, fellow men.

Ultimately, Kanfer's at his best when he's digging into the substance of Bogart's projects rather than the travails of his life, and it's a shame the last section of the book, "Breathless," devoted to Bogart's legacy, isn't a bigger part of Tough Without a Gun. But even if the book were rebalanced, it's possible that Kanfer's trying to explain what's essentially an enigma of moviegoing. In a world where we have more options in entertainment in general and the movies in particular, why do we continue to need Humphrey Bogart? Rick never figured out why Ilsa ended up in his bar in Casablanca. But why isn't really the important part: All that matters is that she's there.