Before dashing for the airport, Nicholson Baker's Checkpoint concealed in my carry-on, I also feel obliged to recommend Hugh Ragin's Revelation. You may remember Ragin from his bolting solos with Roscoe Mitchell and David Murray in the '80s. More recently, a teaching gig in Colorado has been keeping him out of New York, and Revelation has what I suspect is a hidden pedagogical agenda. Ragin and his pianoless quartetwith bassist William Parker, drummer Hamid Drake, and tenor saxophonist and bass clarinetist Assif Tsahargive what amount to a survey course in free jazz, with special emphasis on early Ornette Coleman (trumpet and sax match pitch, then hit it on "Restoration Intensive"), Albert Ayler (on "The Battlefield," Tsahar's lurching bass clarinet hints at free jazz's dark side and Ragin makes like Donald Ayler with chops), and the AACM (a bit of spontaneous sound sculpture on "Skull Hill"). None of it sounds derivative, because Ragin's compositions bounce with glee and his solos jump with as many ideas as they do unusual intervals.