A couple of weeks ago, my two-year-old told his first joke. Bedtime neared, and he brightly declared he wanted to "go night-night with the ducks," who live on our pond. Then he laughed his head off. Now, without going into the quality of his humor (which we naturally think is pretty good for a two-year-old), there is an important point here: He understands what humor is. It's an incongruency, an absurdity. That might seem like a simple and obvious truth, but many of our comedians-the people we pay our hard-earned money to be funny-have forgotten it. Drew Carey isn't funny because he relies on fat jokes and insults. Eddie Murphy has his moments, but too often he relies on profanity (and profanity, by the way, wasn't even funny when Lenny Bruce did it; it was merely scandalous, and people tittered nervously). Steve Martin, though, gets it. His new book, Pure Drivel, has earned its place on the bestseller lists because it's very often funny; Mr. Martin sees the absurdity in contemporary culture and points it out. "Looking out over the East River from my jail cell and still running for public office, I realize I have taken several actions in my life for which I owe public apologies," one of his characters declares as he launches into a litany of ever more far-fetched (and eerily familiar) sins. The apologies are comically Clintonesque. "I would like to apologize for spontaneously yelling the word 'savages' after losing $6,000 in a roulette spin at the Choctaw Nation Casino and Sports Book. When I grew up, the use of this word closely approximated the Hawaiian 'Aloha,' and my use of it in the casino was meant to express, 'Until we meet again.' Now, on with the campaign!" (This, by the way, is why your average liberal doesn't have a sense of humor. When you've been forced by ideology to accept a dozen incongruencies before breakfast-such as the Children's Defense Fund supporting partial-birth abortion-absurdity becomes moot.) Steve Martin has been funny for a long time; his Wild and Crazy Guy character was a bang-on indictment of the disco-era extrovert. His finest work so far is his 1987 movie, Roxanne (rated PG but with sexual content)-a brave updating of Edmond Rostand's classic play Cyrano de Bergerac. Mr. Martin remakes the French swordsman into a Colorado fire chief, but the big nose-and the bigger truths about beauty and virtue-remain. His scene where C.D. Bales comes up with 25 better nose jokes is the equal of Rostand's. In Pure Drivel, though, Mr. Martin turns to today's headlines for his humor and finds an abundance of absurdity. He wonders, for example, how new anti-depressant drugs could change our lives. For one thing, curing depression would really mess up the art world. "Performance artist Shelf-Head 3 has decided to cancel his work 'Frog Slave' and to open a creperie in Brooklyn," Mr. Martin writes. "So he can live closer to his parents ... and he now prefers to be called 'Jeremy.'" The artist denies it has anything to do with his new prescription for Zoloft, Mr. Martin writes, though the drug "is having a worrying effect on art dealers in the anger market." "The artist Screaming Mimi, now 'Cathy,' has summed up this problem in her recent work, 'I enjoy being a girl.'" Pure Drivel is not a G-rated performance; it gets racy (though no worse than the White House antics it spoofs). But those who can handle no-holds-barred satire will appreciate Mr. Martin's drivel-either on the printed page or, for the added bonus of Mr. Martin's excellent comic timing, in audio format.