Introduction
On River: The Joni Letters, Herbie Hancock renews an association with the great singer-songwriter Joni Mitchell, who he first worked with on her celebrated album with Charles Mingus. With producer Larry Klein, he selected thirteen songs, and as Klein has explained, "we used the words to guide us. All of the music emanated from the poetry." They assembled an all-start band to interpret them - Wayne Shorter, Dave Holland, drummer Vinnie Colaiuta, and guitarist Lionel Loueke. Characteristically for Universal, these instrumentalists support a clutch of vocalists, from Corinne Bailey Rae and Norah Jones on "River" and "Court and Spark" respectively, to poet-songwriter Leonard Cohen who recites the dark, surreal lyric to "The Jungle Line" as Hancock freely improvises a solo piano accompaniment. Tina Turner appears on "Edith and the Kingpin," while Brazilian singer Luciana Souza offers "Amelia." Mitchell herself jazzily interprets the autobiographical childhood musings of "Tea Leaf Prophecy".

Abstract
Jazz and politics, the rival merits of swing and even eigths, the relationship between jazz and programme music embodied by Sonny Rollins's Way Out West - these and more exercise former Coltrane and Rollins drummer Pete LaRoca Sims as he reflects on a life in jazz in the presence of Andy Hamilton.

Abstract
Jazz pianist Paul Bley is usually known for his spacious, restrained lyricism, honed with his formative years in the Jimmy Giuffre group and later with music composed by the women in his life, Carla Bley and Annette Peacock. In Bley's 75th year, Andy Hamilton reassesses his career, highlighting his founding role in cementing the early 60s free jazz avant garde with Albert Ayler, Ornette Coleman and Sun Ra, and his pioneering synthesizer and electronics improvisations at the dawn of the 70s.

Abstract
I caught up with David Liebman between his masterclass and concert in Manchester with guitarist Phil Robson's group, featuring bassist Aidan O'Donnell and Liebman's old partner, drummer Jeff Williams. This was the conclusion of a brief UK tour which began with a two-night residence at the Vortex in London. I met the saxophonist in the RNCM cafeteria, a throwback to British cuisine of the 60s. But we were not downcast ­ David was going to eat elsewhere later, and anyway was in talkative mood. As time was quite limited, his verbal tempo in fact seemed to speed up through the interview, but not at the expense of his musical wisdom and good sense. He is, I reckon, one of the most astute and articulate commentators on the music ­ as his sleevenotes to the Mosaic boxed set of The Complete Blue Note Elvin Jones Sessions attest.

Introduction
"I was labelled a free player when I first came to New York. Ornette Coleman and free jazz, that was no problem for me - I would jump on that train too, and have a good time!" But Sonny Simmons has a curious ambivalence towards the free jazz that made his name: "I got sucked into the avantgarde when I was a young cat. I said 'This is the lick, I'm going with it'. But actually, I'd just as rather just play beautiful melodies, with my own compositions, with a groove. That's my true heart. Avant-garde and free, man, that's cool, but it only goes so far ... People want to hear a snap [he clicks a groove with his fingers]." He's done a lot of free playing, so he must have a lot of feeling for it? "Of course I do - if I'm with the right musicians, I can stretch out and play all my ideas within a parameter. But now that I'm in the autumn of my years, I want to come inside again - I've been outside a long time!"

Introduction
Sound as a physical phenomenon has dominated the imagination of avant garde composers during the later 20th century. None has been more obsessed by it than the school of spectral composers. ŒSpectralityš, according to one of its founders, Romanian pioneer Horatiu Radulescu, is not about composers with an interest in the occult or who like dressing up as spooks, but instead involves searching out the "deep structure of sound" revealed in its harmonic spectrum. The search for "Music... older than music", as one of Radulescu's titles has it, was anticipated by Xenakis and Stockhausen, among others. Until this point, Western composition had long spoken the language of tones, defined through melody, harmony and rhythm ­ music which leaves the inner nature of sound unexplored. It's this conception which spectralism challenges. Essentially, the spectralist idea is that one single sound is also a resonant acoustic complex.

Introduction
Plunged at age 16 into the musical experiments of John Cage and his circle, Christian Wolff is America's most enduring minimalist composer. Now well into his sixties, his New York School explorations have reached beyond strict composition into the musics of avantists from AMM to Sonic Youth.

"Chance is used as a way of discovering things," declares Christian Wolff, the American composer whose consistent vision has been to use the force of hazard to 'shape' his enduring, distinctively sparing works. "You could call it a heuristic device," he continues. "Cage once said he looked forward to performances to discover what he'd composed, to be surprised by it. I recall somewhere in Tolstoy's Anna Karenina the story of a painter who got stuck while working on a painting. He gave up on it, put the canvas away in some corner of his studio. Some months later coming back to it he noticed a grease spot or smudge had appeared on it, and then he knew just what to do to finish the picture."