This very technical work is very interesting and uses a very valuable and relatively new approach. However it is very conservative musically, to the point of losing subjectivity. I would recommend James Tenney's writings instead. META + HODOS: A Phenomenology of 20th-Century Musical Materials and an Approach to the Study of Form (1961; Frog Peak, 1988), is available through amazon, or Hierarchical temporal gestalt perception in music : a metric space model with Larry Polansky, also printed in Soundings Vol. 13: The Music of James Tenney. Garland, Peter (Ed.) (Soundings Press, 1984) which has articles by and about Tenney, who takes a much more progressive and broad view than Lerdahl.