POP MUSIC REVIEW : From Peter Pan to Wise Old Man : Jonathan Richman’s concert shows he’ll be forever young--even when singing about being fortysomething.

For some 20 years, Jonathan Richman has been almost invariably described as a pop Peter Pan, an eternal innocent. Well, somewhere along the line when no one was looking, Richman slipped into venerable Wise Old Man-dom.

Not that he seemed at all wizened or the least bit grizzled on the first of three nights at Bogart’s Bohemian Cafe on Wednesday--in fact, he really hasn’t changed a bit, either in his youthful looks or his unchecked, exuberant love for “unsophisticated” rock ‘n’ roll. But while at first glance he may seem like Bruce Springsteen’s simpleton younger brother, in just one song about the joys of being fortysomething he said as much Wednesday as Springsteen did in two full albums last year.

At Bogart’s, Richman, playing guitar and accompanied only by drummer Stephen Hodges, seemed a cross between Big Bird and Dr. David Viscott. He’s a master at finding both the simple truths in complex matters and the complexities of seemingly simple phenomena.

The former came in a series of songs about relationships through which he pretty much laid bare the traps of co-dependency (though, of course, he never used the word). Using wit as his primary tool, he approached the topic with surgical precision on a portrait of a woman who doesn’t realize her relationship is a dead end (“You Can’t Talk to the Dude”), another in which he chronicles his own alleged career as a home-wrecker and then one in which he shows pride and pleasure that his mate has learned to say no to him.

The latter was demonstrated--complete with awkward but unashamed shimmying, in songs about his greatest love of all: rock ‘n’ roll. It’s not just that he understands that “Hang On Sloopy” and the Velvet Underground (both honored with musical quotes) are equals--he can’t believe that anyone could possibly think otherwise.

So universal is the Richman gestalt that Hodges, who had never even met the singer before Wednesday, had no trouble at all following the leader, both on old chestnuts (“Pablo Picasso,” “Egyptian Reggae”), several new works-in-progress and a few spontaneous bursts of rough-hewed surf-style guitar workouts.

So distinct and individual is he that no matter how many countless young innocents have tried to follow his pattern, there will always be just one Jojo. He’s no case of arrested development, but someone advanced enough to know that the basic truths don’t change with age--or with the ages. Richman concludes his Bogart’s stint tonight. He plays the Palomino in North Hollywood on Saturday and the Belly Up in Solana Beach on Monday.

Fittingly, Richman’s opening act was hardly your typical sight in a rock club: the D.T.’s, two senior-citizen gentlemen with ukuleles, playing, well, the kind of songs you’d expect from two senior citizens with ukuleles--a delightful and utterly appropriate tone-setter for the night.