In another quarter-century this film will reside in reference libraries, filed alongside dusty tomes about The Gold Rush and The Dawn Of Hollywood, to be scrutinised by students researching the pivotal moments in American social history. Should they chance first upon the rain sequence, all ten mood-dampening minutes of it, they might think they're watching a documentary about vanishing tribes, in this instance an insanely sociable late 20th Century species that can subsist almost entirely on marijuana, drum solos and occasional parcels of flowers and dry clothes dropped by helicopters, scooting butt-naked down improvised mud-chutes while friends chant and pat tom-toms.
As a piece of entertainment, however, and one a full 20 minutes longer than Schindler's List, it's pretty relentless. Even for someone like me who saw the original in 1970 and was fascinated, though not surprised, to discover that all the acts they loved when they were 16 (Jefferson Airplane, Ten Years After, etc) are a bit useless and the ones they found baffling or dull (Sly Stone, Richie Havens, etc) are extremely wonderful. Likewise the prevailing tone of beatific oneness now seems faintly quaint, the most enduring moments coming less from the stage - additional footage includes Canned Heat, Janis Joplin and a mesmerising Hendrix wig-out - and more from the rare flashes of tension: a girl desperate to escape, irate locals, and an eerie sequence in which volunteers load acid casualties on to an army helicopter, virtually indistinguishable from the Vietnam newsreels that both haunted Woodstock and fuelled its very existence.
Filmic footnote: The assistant director was one Martin Scorsese.