The Mode label continues its series of releases devoted to the music of Christian Wolff -- this is the sixth volume -- with a wide-ranging selection of chamber music spanning 37 years of the composer's career, from 1962's "For 5 or 10 Players" (heard in two versions, understandably enough one for five players and the other for ten) to 1999's "Schoenen Met Veters," written for and performed by (as is all the music here) the Barton Workshop. The ensemble's trombonist and musical director, James Fulkerson, provides brief but cogent liner notes that rightly lay stress on the composer's continued fascination with contrapuntal artifice, notably writing that embodies the techniques of canon and hocket, but the music, deceptively simple though it might appear at times, is far removed from sterile neo-classicism. Indeed, a technique such as hocket -- in which a melody is shared between different instruments -- is the perfect metaphor for Wolff's vision of working together, as the composer's concern for humanism and political and social justice is never far below the surface. But even explicitly titled works such as "Peace March I ('Stop Using Uranium')" never fall into the trap that ensnared Cornelius Cardew's late music -- writing music that can appeal to the general public as opposed to a tiny audience of new music aficionados doesn't necessarily mean adopting a lowest common denominator approach: "Violist Pieces" (1997), performed with exemplary precision by Elisabeth Smalt, the earlier "Digger Song" (1988), and "Emma" (1989) are superb examples of Wolff's ability to create music that is technically challenging, even virtuosic, without ever being flashy. If John Cage is the father figure behind the chilly experimentalism of "For 5 or 10 Players," then Charles Ives is the grandfather -- witness the boisterous angular folk music of 1979's "Three Pieces" for violin and viola. And, as with the music of Ives and Cage, the notes chosen aren't necessarily the easiest on the ear, but the integrity that led to their creation is unquestionable.