Arc of Testimony is one of the last recordings to feature legendary drummer Tony Williams, and its bold, experimental textures are a fitting epitaph to his career. Arcana was formed by bassist/producer Bill Laswell with the intention of exploring the outer reaches of fusion, ambient and free jazz. Like the group's debut, Last Wave (released only in Japan), Arc of the Testimony is a freewheeling, unpredictable blend of electronic and acoustic sounds. However, this record is even more adventurous, since it finds a common ground between improvisation and post-production studio trickery. All of the musicians -- Williams, Laswell, saxophonist Pharoah Sanders, saxophonist Byard Lancaster, cornetist Graham Haynes, guitarist Nicky Skopelitis and guitarist Buckethead -- are open-minded and help push the music forward, resulting in a thoroughly involving, challenging listen.