This collection features The Grateful Dead's May 23-24 sets at the 1969 Big Rock Pow Wow festival held on a Seminole reservation in Florida; it could be seen as a companion piece to the legendary Live/Dead album, which was recorded at a string of shows a few months earlier. With the addition of keyboardist Tom Constanten, whose avant-garde leanings pushed the band further toward the experimental side, the Dead were a magnificent, seven-headed beast by this point. While they were still fully capable of tapping into their blues influences with Rev. Gary Davis's doomy "Death Don't Have No Mercy" and their soul side on Otis Redding's "Hard to Handle" (both featuring the Dead's roots maven Pigpen on vocals), the band's explorations of the sonic stratosphere on epic versions of outward-bound tunes like "The Eleven" and the open-ended "Dark Star" show them to be psychedelic warriors bent on collapsing the constrictions of conventional rock 'n' roll. And when Weir kills time during a string change with his "Yellow Dog Story," he shows an undeniable knack for bad jokes.