Long Strange Trip is a Grateful Dead documentary produced by the band, their families, Martin Scorsese and David Lemieux; the archivist best known for getting distracted by nature.

At 4 hours this is one for the completists (and to be a Deadhead is to be a completist) but director Amir Bar-Lev makes stellar use of the Dead’s sprawling archives and fabled history, telling overlapping stories in the style of the jam band’s conversational music. Besides, a Grateful Dead doc under 4 hours would just seem wrong.

With contributions from everyone you’d hope for including guitarist/vocalist Bob Weir (born cross-eyed, sat cross-legged) and percussionist Mickey Hart (“We’re in the transportation business”), the movie charts the group’s journey from pizza parlour jugsters to Acid Test house band to touring behemoth and American institution; a long strange trip littered with wild characters (eg. Ken Kesey and Owsley ‘Bear’ Stanley) and heady stories, most of which end with someone dosing the coffee with LSD.

One of these characters, lyricist John Perry Barlow discusses the Dead’s “utter comfort with paradox”; the kind of paradox he exemplifies by virtue of being a cattle rancher and internet pioneer, among many other things. This sense of paradox shrouds the Grateful Dead, from its strange brew of cosmic jazz and cowboy songs to the irony of a band dedicated to spontaneity becoming the most catalogued and obsessed over in history.

Even the name seems paradoxical, both in relation to the music and to itself. But death emerges as the film’s focus, characterising the Grateful Dead as Frankenstein’s Monster. The character was a long-time obsession of Jerry Garcia, who wanted to create something that was truly alive even though its 80-show-a-year touring schedule (and decades of self-medication) ended up killing him.

Garcia’s wife Barbara ‘Brigid’ Meier recalls Jerry (after Ben & Jerry’s named Cherry Garcia after him) talking about quitting the band and “living off the ice cream money”, which sounds like a wholly appealing concept. But like the documentary Amy, there were too many people invested in Garcia’s continuation (the audience had essentially been part of the band since the Acid Test days) and his commitment to freedom meant he never wanted to say no.

This is the film’s final paradox: “Where’s the freedom in that?” asks Meier; a tough pill to swallow for Deadheads but a) we’re used to that sort of thing and b) this movie is a real gift for fans, with the ebb and flow of a Dead show; a four-hour trip that’s sometimes a party, other times reflective and always full of Hart and Weir-dness.