TWO YEARS AGO Boz Scaggs was not attracting much attention. Despite a long career as a prominent session man and several well-respected albums, the beginning of '76 found him virtually nowhere on the all-important scale of commercial success. Several of his songs--"Loan Me a Dime," for example, and "Dinah Flo" were FM classics, but FM airplay is a notoriously poor way to pay the rent. It was the old story--a critical acclaim and cult following which did not translate into anything tangible and preferably green. His gradual evolution from rock to a bland middle-of-the-road sound just wasn't making it and he was due for either a radical change or more years in obscurity.

Scaggs opted, not surpisingly, for the change. "Silk Degrees," arguably the biggest hit last season by an artist or group not including Mick Fleet-wood, was a monolith, spinning off three hit singles and booming Boz Scaggs squarely into the Top 40 spotlight. His concerts, never before especially noteworthy, were suddenly sellouts. The days of the six-piece Texas blues band and the scruffy cowboy threads were gone forever; Boz was fronting a full orchestra and twirling stylishly onto the stage in silk scarves, Cardin suits and Gucci loafers. The image, after all, fit the music--slick and seamless pop, immaculately produced and maddeningly catchy. It flirted dangerously close to disco without ever quite stepping over the line, and it worked. Millions of albums sold and Boz Scaggs gained mass acceptance for the first time.

For all intents and purposes, "Silk Degrees" was Scagg's first album--the one that established him as a high-fashion god of blue-eyed soul in the ears and minds of the record-buying public. The question then became, could he do it again, and do it as well?

"Down Two Then Left" doesn't really answer that question in any kind of satisfactory way. It's a spotty album, more or less evenly divided between rather decisive failures when Scaggs plays safe and surprising triumphs when he takes some risks. All in all, the good cuts are much more ambitious and complex than anything on "Silk Degrees," and the bad ones make one wish he'd gone down fighting instead of taking the easy way out.

Scaggs may be one album beyond "Silk Degrees," but never let it be said that Scaggs is one to forget from whence he came. The very first cut on the record, "Still Falling For You," is almost a note-for-note copy of "Lowdown," from the beat to the flute background to the rimshot percussion accent. Still, it is a better song than "Lowdown"--mellower, although the brass charts are pleasantly aggressive, and more lyrical overall. The chorus is a nice surprise, employing an unexpected chord progression that grows maddeningly on the listener despite the fact that it's virtually impossible to whistle, sing or hum. "Gimme the Goods" revives the sad small-time hoods of "Lido Shuffle," still looking for that one last job to put them on Easy Street. This time, the tune is much more funky, a roaring big-band epic that pulls out all the stops. Steve Lukather kicks in a gine guitar solo here, and its passion points up the relative sterility of all the hoopla framing it. (Jay Graydon, lately of "Doonesbury" fame, has the same effect on "Then She Walked Away"--his ringing, simple guitar makes the rest of the elaborate orchestration sound a bit silly.)

But the album's strongest cuts are the ones that are unlike "Silk Degrees," the ones that diverge from it or take it a step further. They show how good Scaggs can be when he sticks his neck out a little. "1993," an appropriately spacy tung, is closer to rock and roll than anything he's played for years. There's nothing fancy here, beyond some tricky synthesizer effects; nothing lyrically precious or musically cute. In that it's a return to basics, it's a divergence from the style Scaggs has come to be known for, and it works. Jeff Porcaro's drumming is unspectacular, but so steady that one wishes he'd be cut free of the quasi-disco beat earlier.

The album's best track is "Hollywood." Look for this song to be blasting out of jukeboxes and car radios across America very soon. It quite literally has everything--a musical hook that won't quit; a lyric tag you won't be able to forget; strong, simple orchestration; and best of all, a sly and casual vocal with Scaggs fitting his voice to the lyrics as well as he's ever done. The song is fully within the "Silk Degrees" style, but it shows a sure touch, a confidence and sense of command that's nowhere in evidence on the earlier album.

The cuts where Scaggs hangs back and plays safe are not particularly outstanding. "A Clue" is pretty and lyrical and at the same time thoughtful and boring; the crashing of cymbals in "We're Waiting" is meaningless and facile; "Tomorrow Never Came" is pure filler. Half of the songs on the album just don't work, and are failures made all the more disappointing by the excellence of the other half of the album. Scaggs may have cut his own throat on this record by not sustaining high standards the whole way through, but if his fans stick with him through the low points on this album (as they should), the promise of what he may do in the future looks great.