This book explores the performances of Miles Davis’s “Lost” Quintet, 1968-1970, to illuminate the unfolding of Davis’s musical thinking during a period of personal transition. A careful listening reveals music that privileged an uneasy dynamic tension between, on one hand, sonic and structural openness, surprise, and experimentation and, on the other hand, the rhythmic groove. Viewing Davis’s band in this manner allows new webs of musical interconnection to emerge—not only continuity with Davis’s subsequent funk inflected bands—but also a musical world pioneered most significantly by Ornette Coleman. Davis’s musical peers come to include highly exploratory bands including Circle (co-founded by two members of the “Lost” Quintet) and the Revolutionary Ensemble. This book provides a consideration of the aesthetics and performance practices of all three bands and others in which Circle saxophonist Anthony Braxton played, in search of points of musical resonance. This work concludes by acknowledging a profound distance that lay between Miles Davis and these peers within the musical economy. Elements include access to financial resources, recording contracts, bookings, and the ability to reach an interested public. This work in its fullness thus encompasses yet moves beyond musical aesthetics to explore a fascinating period of discovery and new possibilities emerging within American musical history.