The late guitarist Derek Bailey is often festooned with such mouthfuls of honorific as "the grandfather of British non-idiomatic free improvisation" which if true would have to make drummer Tony Oxley a great uncle, and a fine one at that. Bailey and Oxley were there at the dawn of British-non-idiomatic-free-improvisation time (c 1963) in the trio Joseph Holbrooke with bassist Gavin Bryars and the two worked together on and off in various assemblages (often as a duo) until Bailey's death in 2005. They were also (with saxophonist Evan Parker) the founders of the record label Incus, (now maintained by Bailey's wife Karen Bookman), on which this collection — compiled for Oxley's 75th birthday — is issued.

Bailey is only present on two of the five tracks here, but with the stellar opener clocking in at 29:00 that still makes for more than half the playing time. That piece, "Colour Fields" and the four-minute follow-up "Urban Forms," both recorded in 1993, are wonderfully knotty affairs distinguished by the screwy keyboards of Pat Thomas and the authoritative voices and cloudy soundbeds that emanate from Matt Wand's sampler. It is an excellent helping of that free-improv trope of a group of musicians playing against each other, without each other, occasionally together but never beholden to one another. Oxley's light and busy percussion often fills the sound space but the music is guided by swarm intelligence: like the flocking behavior of birds, the 35 minutes of music the quartet plays has no leader but has direction by each falling more or less in with the sounds immediately around them.

For the second half of the program we're jettisoned back to 1977 for a solo, a duet and a trio, employing different playmates and considerable use of electronics. "Kelson" is seven minutes of tense ambiance performed with trombonist Paul Rutherford. The whooshing, metallic sounds of the electronic effects and amplified percussion do make it something of a period piece, but it's a fun piece of work, a duo conversation exploded into multiple layers. "The Earth Sounds" also sounds like a product of its time (that being a descriptive point and not an aesthetic judgment). Guitarist Ian Brighton has a pointillistic style similar to Bailey's but with less jagged edges, while the scrapings of Phillip Wachsman's violin fall beautifully alongside Oxley's amplified cymbals. The final track, "Times," stands up to the test of time better than the other two 1977 pieces. Here Oxley is heard playing solo, masterfully riding a wave of modulating tones and augmenting them with tasteful cymbal work. It's an unlikely, and quite nice, closer.