Birds of Fire brings overdue critical attention to fusion, a musical idiom that emerged as young musicians blended elements of jazz, rock, and funk in the late 1960s and 1970s. At the time, fusion was disparaged by jazz writers and ignored by rock critics. In the years since, it has come to be seen as a commercially driven jazz substyle. Fusion never did coalesce into a genre. In Birds of Fire, Kevin Fellezs contends that hybridity was...