Every time Robert Blake thinks he has the world on a string, it turns out to be a yoyo. He escaped from a dead-end Italian neighborhood in New Jersey to become a kiddie star in the Our Gang series in the 1940s, then skidded into alcoholism and drugs as a teenage has-been. He made a comeback in 1967 with a shattering portrayal of a death-row killer in Truman Capote's In Cold Blood. Then the moody, erratic Blake crashed again into a mental depression ("Jewish brain fever" is his term for it) and required psychiatric help. This spring, at 41, Bobby Blake seems once again to be spinning to the top as the Columbo-esque undercover cop in ABC's new sleeper hit, Baretta.

None of Blake's tortuous, tortured history has exactly been a secret since he began turning the TV talk-show circuit into his personal encounter group. In front of Merv Griffin and 4 million other stunned auditors, Blake confided, "I've sold dope, used it, snorted it, done everything you can do to it." Some tapings, Blake even shocked himself. "That chair on The Tonight Show is as scary as the electric chair," he says. "Sometimes I'd come off the air and want to blow my brains out. But the talk shows probably did more than anything to change my life—except for my wife."

His wife, Sondra, 32, is the anchor in Blake's bobbing world. An actress he met at the Pasadena Playhouse (her name was Kerr then), she has worked with him in creating the feisty detective Baretta, who with his pet cockatoo, quirky disguises and oddball humor is one of TV's more appealing cops. There is not a little of Blake's own upbringing in the characterization. Born Michael Gubitosi, he worked in his parents' song-and-dance act called "The Hillbillies" at age 2. It was not successful (Blake, as he started calling himself in 1948, remembers being sent out to steal milk), and the family re-located to L.A. He started as a movie extra at $2.60 a day in the Our Gang series, then played "Little Beaver" in the Red Ryder Westerns and even sold a newspaper to Bogie in Treasure of the Sierra Madre. But it was no fun. "I wasn't a child star," he says. "I was a child laborer."

At 16, Blake ran away from home, wound up in the Army (where he did some stockade time) and didn't pull himself together until he went back to acting. About the only thing Bobby never let himself get hooked on was success. He would get a run of good TV roles (as in The Richard Boone Show or The FBI) and then muck it up by punching a director in the face. In Cold Blood, which should have been a launching pad, threw him into a psychological tailspin, and he was unable to work for two years. His next four pictures, from Tell Them Willie Boy Is Here to Busting, were turkeys. Then Blake lost out to Dustin Hoffman for the lead in Lenny and fumbled a chance for the James Caan part in Funny Lady out of pique with Barbra Streisand for having made him audition.

With Baretta, Blake has earned an unexpected new sublease on life. "All the wizards told me I was crazy to do it," he says. "But I've made a lot of dumb moves listening to voices of authority who don't know their own ass." When Baretta premiered in January, it was destroyed in the ratings by NBC's Police Woman. Then this month ABC switched the show to a more advantageous Wednesday slot, and the Nielsens have zoomed. Even with the turnaround and assurance of renewal for next season, Blake is still a bandy-legged, walking landmine. Just as this spring's shooting was winding down, the mercurial Blake stayed home and there was a shake-up of the show's producers.

After being burned so many times by success—and by his own bluntness—Blake reacts fatalistically. His lifestyle with Sondra and the two kids is resolutely non-Hollywood. "Anyone who doesn't wear a suit," he says, "is a friend of mine." Once Blake showed up at Johnny Carson's house in a fishnet sweater. "You didn't have to dress," cracked Carson. "He didn't," Sondra shot back. "It's a rented sweater."

"When you croak, what'll they talk about?" asks Blake. "I hope my kids will be more impressed with the job I did on this show than with the limousine that picks me up in the morning. I want to give them what I didn't get—a father who can do something." Is he finally satisfied on that point? "I wouldn't say Bobby's content," reports a colleague. "He's not the kind who aims for contentment." The best Blake will say for himself is that he has "bounced back" from his earlier trouble "much the better for it." As for the Hollywood people "who didn't want me around earlier, they're dead now or selling shoes."