Joni Mitchell: Blue (Reprise MS 2038).

Writing 10 or 12 original songs for a record album is a more difficult accomplishment than most people realize. Writing the material for four albums in a period of two and a half years or so, as Joni Mitchell has done, is enough to boggle the mind-she has managed to sustain, in that time, a relatively persistent artistic momentum.

This latest release represents a more enigmatic step forward than any of the others. The title is well chosen, since it reveals a womanly melancholy that is new to Miss Mitchell. Her voice, no doubt reflecting the influence of James Taylor, slips and slides, moves in and out of the rhythm, plays with words and announces her maturity as a performer.

The songs reach out I all directions. Predictably, they provide a mind's eye view of Miss Mitchell's lives and loves, and she clearly is no longer the innocent of her earlier days. We now hear about trips to Paris and Greece and Amsterdam, about winds from Africa, and her distaste for the thought that "hell is the hippest way to go." Touches of the old whimsy remain in songs like "A Case of You" and "The Last Time I Saw Richard," but for the most part the mood is introspective and somber-sometimes passionately so.

I suspect this will be the most disliked of Miss Mitchell's recordings, despite the fact that it attempts more and makes greater demands on her talent than any of the others. The audience for art songs is far smaller than that for folk ballads, and Joni Mitchell is on the verge of having to make a decision between the two.