FROM HER EARLIEST songs, Joni Mitchell has displayed an extraordinary capacity for understanding the role change plays in people's lives. On her newest album, Hejira (Asylum 7E-1087), she has put into words the distance and closeness she feels towards others and herself as a result of a demanding wanderlust.

As dramatic a departure from her previous three albums as Blue was to her first three, Hejira (which means Mohammed's flight from Mecca and symbolizes other, similar escapes) is Mitchell's attempt to come to terms with her erratic ways of discovering and abandoning lovers while constantly moving from place to place. But now, at least, it's she who makes the decision to leave.

On this new work, Joni has transcended the jazz-rock influences of Court and Spark and the L.A. Express (and the folk nature of her music before then) in favor of a style that is completely of her own making. Her stint with Dylan's Rolling Thunder Revue last year must have had an impact, for she is asserting herself more as an individual performer again with less reliance on a group sound.

FEW SONGS here have more than three musicians performing them and Joni (for the moment) has all but given up playing the piano. It makes each tune less distinct from the others than in the past but that's part of her plan. The album is basically of a series of moody ballads - some fast and some slow - that gradually build in feeling and meaning so, by the end, the listeners has gone through one encompassing experience rather than nine separate ones.

She sets the tone of the LP with the assertion, on the opening "Coyote," that she's "a prisoner of the white lines on the freeway" and sums it up on the closing number by speaking of "the refuge of the roads." In between, she compares her lost but free coul [sic] with Amelia Earhart's, recounts a disillusioning encounter with blues great W.C. Handy and analyzes a wide variety of different relationships.

But, make no mistakes about it, she has learned (and is now presenting) her lessons well enough to realize that going in a new direction doesn't always turn out for the better. Yet, she refuses to be held back by the pain she might have to face later on. In the title song, she notes:

I'm so glad to be on my own... I know - no one's going To show me everything We all come and go unknown

IT'S A WRY, almost cynical, outlook for this bright-eyed dreamer from Canada to have but Mitchell has come to adjust to and be happy with the fact of being alone. In the powerful "Song for Sharon," she admits

Love's a repetitious danger You'd think I'd be accustomed to Well, I do accept the changes At least better than I used to do

but also willingly confesses that all she really wants in her extensive travelling "is to find another lover!"

Every piece has its own chemistry working for it while sharing an interrelated common ground of images and themes with the other eight. Complex and flowing, they show an returning emphasis on the acoustic guitar and her innovative vocals. She keeps the jazz and rock passages to a minimum in order to heighten their effect when she does use them.

The performances and production are superlative even by the standards set by her recent releases. From Neil Youngs' haunting harmonica on "Furry Sings The Blues" and Larry Carlton's intricate electric guitar riffs, to her experiment with three different types of bass playing (the most notable being Jaco Pastorius' contribution on "Refuge Of the Roads"), it's one musical treat after another. Likewise, the album's artwork is a direct outgrowth of the material contained within.

During her February concert at Hill Auditorium, Mitchell sang a new song called "Don Juan's Reckless Daughter." In it, she identified as she does more fully on this LP, with being a restless lover who is following "a path with a heart." It is often a lonely way but, as she has shown once more, it is sometimes the truest one to take.