"In Through the Out Door" is Led Zeppelin's ninth LP release to date. During its first month on sale nearly 2 million copies changed hands. In the industry's parlance, it's practically "gone double platinum," already topping the LP charts.

When you see it displayed in retail stores, the album is packaged in a plain brown paper bag. However, inside the bag one discovers a second jacket, the "real" one -- or at least one of them.

"In Through the Out Door" has six different cover designs in all, minor variations on a central image. In each, a man dressed in beige pinstipes sits in a seedy bistro toying with paper and cigarette lighter. Taken in sequence, the covers depict him setting fire to the former with the latter. Each one shows the scene from the varying perspectives of six other people in the room.

It's a cleverly contrived statement, skillfully executed. Great attention has been paid to minute detail; every last cigarette butt and beer stein stands out vividly.

But for all that, it's an empty gesture, a pointless exercise. Nothing is communicated, no information is conveyed. From the outset, none was being volunteered. This is the problem with what goes on inside the jacket as well.

Led Zeppelin emerged from the ashes of the legendary Yardbirds at the heighth of the blues craze that swept Great Britain in the late '60s. They were immensely popular from the very first.

The band's sound was a monstrous exaggeration of the original blues-men's fascination with the "riff" -- a short, easily identified burst of notes. Their image was an equally bombastic overstatement of that oppressed class' necessary doctrine of self concern, emphasizing its sexual aspects.

The combination proved irresistible to confused, impressionable adolescents. The blatant music afforded instant accessibility. The rigid, exploitative steriotyping of sex roles appealed immediately to identity-starved teens.

In the years since, the group has moved away from these rude beginnings. They dabbled with other influences: folk; classical; reggae. They began alternating their sexual fables with more esoteric ones. In other words, they went "progressive."

"In Through the Out Door" gives a token nod to the blues, a show of punk-inspired rootsmanship. The song "I'm Gonna Crawl" is a slow, sensuous Memphis blues a la Otis Redding. The effect is spoiled by the intrusion of a huge churchy pipe organ (or synthesized equivalent thereof).

Elsewhere they take ham-fisted, stabs at rockability ("Hot Dog"), boogie woogie ("South Bound Saurez"), space rock cum disco ("Carouselanbra") and so on. But all to no avail.

The problem is not one of musicianship, though from the evidence here it appears that they've been horribly overrated by friends and foes alike. Neither is it a problem of presentation. Jimmy Page's production is often quite diverting and his composing gimmicks keep the listener's interest constantly engaged, if not stoked.

No, what "In Through the Out Door" lacks is the slightest sense of motivation or intent.

For all his self-obsession, Robert Plant's lyrics reveal nothing of his inner workings. Instead, he halfheartedly manipulates a handful of all-too-predictable catch phrases in order to elicit the usual conditioned response from the fans. Or perhaps these are his true feelings. Yipes!

Meanwhile, his cohorts saunter dispassionately from style to style. There are no great archetypal riffs for songs to revolve upon. They've lost the knack, or perhaps the will. Rather, songs rely on softboiled eclecticism and muddled, needlessly complex structuring tricks to keep the listener involved. And none too successfully at that.

By and large, "In Through the Out Door" is merely an excuse to display technique, bask in the fans' blind devotion and reap the bucks.

Led Zeppelin have already established themselves as a cultural institution, so none of this really matters in the end. Their fans are hooked on the group's aura of success and omnipotence, and that's that.

The supply of perplexed teen-agers will probably never run low. At the same time, the age of those afflicted seems to rise each year. Led Zeppelin have nothing to worry about.

Led Zeppelin, "In Through the Out Door," Swan Song Records, SS-16002.