Not many musical acts in human history attracted the cult following and counter-cultural status of The Grateful Dead, a band that, as the AV Club puts it, "at its height, was simultaneously a working musical group, a subculture in its own right, and the nexus of what was, essentially, a traveling town of hippies and societal drop-outs." Now director Amir Bar-Lev is debuting a four-hour documentary about the band's beginnings, and its legacy, titled Long Strange Trip, which opens in theaters on May 26 and premieres on Amazon Prime on July 2.

As you can see in the trailer, there's plenty of talk about how LSD helped form the original "group mind" of the band, and the film also includes never-before-seen concert and archival footage, new interviews, and the story of the fabled Wall Of Sound.

Martin Scorsese served as an executive producer, but so did a long list of folks: Emma Tillinger Koskoff, Rick Yorn, Thomas J. Mangan IV, Alicia Sams, Andy Heller, Sandy Heller and surviving Grateful Dead members Mickey Hart, Bill Kreutzmann, Phil Lesh and Bob Weir.

As Jambase notes, "Long Strange Trip marks the first time Amazon Original Movies and Amazon Original Series have partnered on an original project to be released in both theaters and on Prime."

Below, a Q&A with Bob Weir, director Bar-Lev, and several others at the Mill Valley Film Festival this week.