It’s strange that more jazz musicians haven’t covered the Mitchell songbook. Her harmonies are sophisticated but also wide open, leaving plenty of freedom for improvisers. Dave Douglas recorded a few of her songs, and several others that he wrote in her spirit, on his 1998 Moving Portrait. Fred Hersch often plays “My Old Man” in concert (he recorded it on Let Yourself Go). And Mitchell’s more adventurous albums—Mingus, Hejira, and The Hissing of Summer Lawns (which, besides Blue, are my favorites)—have an overt jazz inflection as well as occasional guest spots by Hancock and Shorter.

River is, at last, an album devoted entirely to opening the possibilities of a jazz-Joni fusion—and “fusion” here should be taken literally: not as some ramshackle bric-a-brac but as a seamless merging. This is unmistakably a jazz album and a Joni Mitchell album; there’s no contradiction in the terms.

Hancock’s rich, airy tone clusters, which he’s been weaving since the early ‘60s, fit perfectly with Mitchell’s spacious chords. Shorter has been known, in recent years, to doodle on soprano sax, but he hits his mark on these sessions. But it’s Dave Holland who, in many subtle ways, propels this music forward. On the album’s instrumental tracks, most notably “Both Sides Now,” Hancock often tosses out a chord and lets the overtones bloom; a good bassist has to fill the space but in a way that adds tension, not clutter; in that sense, Holland is a great bassist.

The singers are also, for the most part, a shrewdly chosen lot: a winning Norah Jones on “Court and Spark,” a sassy Tina Turner on “Edith and the Kingdom,” Lucia Souza doing a dead-on mature Joni on “Amelia,” and Joni herself getting down and smoky and free-wheeling on “Tea Leaf Prophecy.” (If anyone doubts Mitchell’s prowess as a jazz singer, take a listen.) The only eh vocal tracks are by Corinne Bailey Rae, who strains across the title song, and Leonard Cohen, who croaks through “The Jungle Line” (is he supposed to be funny?).

River is a bit of a comeback album for Mitchell, Hancock, and Shorter; all three have fallen far short of their peaks in the past decade or so of studio dates. Next time, they should do a whole jazz-and-Joni album.