Historic debate over the relevance and merits of trumpeter Miles Davis' seminal jazz-rock fusion masterwork Bitches Brew (Columbia), especially upon this year's 40th anniversary of its original 1970 release, could fill every page of even a paperless internet jazz e-zine (a body of work to which Greg Tate's companion essay adds: "Bitches is a multi-clawed, multi-tentacled, multi-brained creature whose center of gravity never stays preoccupied with one body part for too long"). But one point seems certain: two live performances of this electrifying music—one from 1969 on a bonus DVD, the other from 1970 on a bonus CD—are the genuine treasure troves of this 40th anniversary Collectors' Edition.