Porcupine Tree drummer Gavin Harrison just announced via his Facebook page that he'll be releasing a new book that he co-authored with Terry Branum titled Rhythmic Composition: Featuring the Music of Porcupine Tree. The book contains twenty highly detailed transcriptions by Terry Branam and in-depth commentary from Gavin, along with over 40 great photos and a foreword by Neil Peart. Amazon has a release date of May 2nd listed and you can pre-order your copy here (thanks RushFanForever).