Bassist William Parker is best – and rightly – known as a monumental pillar of the global free-jazz community, but his long-standing quartet, which forms the backbone of this magnificent box-set, very rarely plays free-jazz per se. Instead, Parker, Drake, Brown and Barnes come over as something akin to a psycho-spiritually liberated hard bop unit, dedicated to exploring Parker's tough but openhearted compositions. There is freedom, for sure, but it's in the quartet's ability to range across different forms during the course of a jam: from hard-swinging blues to springy free-bop, from deep reggae grooves to Arabic-tinged modality, for which Parker breaks out a keening double-reed instrument. At the bottom of it all lies Parker's instinctive ability to latch onto some of the deepest grooves in the galaxy. The quartet plays on all seven of these previously unreleased concerts, presented across eight discs – with additions and augmentations: expanded to a septet for a one-time-only appearance with the late violinist Billy Bang, plus veteran horns-men Bobby Bradford and James Spaulding; and swollen to the 12-piece Creation Ensemble. The final two discs offer two distinct groups, both playing allnew compositions – and give the best indication of Parker's range and generosity. Raining On the Moon is a sextet featuring pianist Eri Yamamoto and vocalist Leena Conquest's soulful delivery of Parker's heartfelt, consciousness-raising lyrics. In Order To Survive – featuring idiosyncratic pianist Cooper-Moor – was Parker's principal small group before the quartet, here reunited for a fierce and turbulent set that comes closest to free-jazz. But forget the genre labels: it's all utterly indispensable.