This live album, which captures The Paul Butterfield Blues Band in their short-lived prime, will answer any doubters’ questions about why these guys were inducted into the Rock and Roll Hall of Fame in 2015. Born out of Chicago’s vibrant blues scene of the 1960s, this sextet (one of rock’s first interracial groups) boasted two virtuoso musicians—Butterfield on harmonica and Michael Bloomfield on guitar—as well as guitarist Elvin Bishop (Like Butterfield and Bloomfield, a Blues Music Hall of Famer), organist Mark Naftalin, former Howlin’ Wolf bassist Jerome Arnold and veteran blues drummer Billy Davenport. This recording comes from a performance in a small Boston folk club, done between their self-titled 1965 debut and their fabled 1966 effort East-West (their last album with Bloomfield). Blues disciples who played with rock-and-roll fervor, the band sounds like a force of nature from their opening, a razor-sharp rendition of Elmore James’ “Look Over Yonder’s Wall,” straight through their set closer—a rousing five-minute workout of “Got My Mojo Working.” Considering this is an audience recording from 1966, the sound quality is pretty decent. Although Butterfield’s vocals get somewhat lost in the mix, the band’s playing comes across more clearly. This hour-long set boasts numerous highlights: the interplay of Butterfield’s harmonica and Bloomfield’s guitar on the old Tampa Red tune “Love Her with a Feeling” (which the band never recorded), the funkiness that Naftalin’s organ adds to Allen Toussaint’s “Get Out of My Life, Woman,” and the way Bloomfield and Bishop’s guitars duel on a fiery take of Smokey Robinson’s “One More Heartache,” as well as on the slinkier title track. The set’s centerpiece, however, is their epic 12-plus-minute version of Nat Adderley’s jazz standard “Work Song.” While everyone shines during this instrumental, Butterfield’s herculean harmonica-playing and the expansive guitar work by Bishop and, especially, Bloomfield are, as they might have said in ‘66, “mind-blowing, man.”