Herbie Hancock's new album, "River: The Joni Letters" (Verve), pays tribute to a pair of musical geniuses: Joni Mitchell, whose songs make up the album's marrow, and Wayne Shorter, the extraordinary saxophonist and longtime Hancock collaborator who steals the recording. Working with a rotating cast of vocalists, Hancock, Shorter, and company tap into the moody and meditative nature of songs that work best when their musical poetry is respected.

Hancock, who spent the sixties establishing himself as one of the most accomplished and inventive modern-jazz pianists, apparently tuned out Mitchell's early folk albums. Apart from the title track and a thoroughly reworked "Both Sides Now," Hancock trains his sights on Mitchell's jazzier material, from "Court and Spark" (released in 1974) and beyond. Hancock keeps the album rooted in spare, predominantly acoustic arrangements, yet avoids the temptation to transform Mitchell's songs into mere vessels for charging improvisations.

Given that these songs are inseparable from their creator, the singers do what they can to stay afloat. Norah Jones glides through "Court and Spark," Tina Turner sasses "Edith and the Kingpin," Corinne Bailey Rae purrs the now overexposed "River," and Luciana Souza intones a calming "Amelia." (Leonard Cohen signs off with a deep-from-the-tomb spoken-word version of "The Jungle Line.") Modestly slipping in for "Tea Leaf Prophecy," Mitchell herself makes lightweights of them all. Though the tonal purity and agile range of her youth are long gone, she remains a master of rhythmic phrasing and unforced emotional expressionthe ideal interpreter of her own work.

Hancock plays with care and beauty, his understated lyricism infusing the instrumental features "Sweet Bird," "Both Sides Now," and Duke Ellington's "Solitude," one of two non-Mitchell songs. But it is Shorter who truly inhabits Mitchell's unique musical universe; relying on suggestion and shading, his compact soprano and tenor saxophone lines deliver the impact of ten notes with just one. Shorter gets to stretch out on his own composition, "Nefertiti," the spiraling number that, in its debut on Miles Davis's 1967 album of the same name, gave notice that the saxophonist was on the cusp of becoming a major jazz figure. Here, it acts as an homage to the artistic daring of three soul siblings: Joni, Wayne, and Herbie.