The title stands for "Mobile Army Surgical Hospital", the setting for Robert Altman's Oscar-winning comedy about maverick surgeons up to their smocks in blood, guts, and bullets. The conflict here is Korea, although for millions of moviegoers the satire crystallised their objections to another, far more pressing concern - Vietnam.
Elliott Gould and Donald Sutherland play Trapper John McIntyre and Hawkeye Pierce, a couple of irreverent medics stationed near the front line who hatch madcap schemes and wild adventures to take their minds off their grisly duties.
Their exploits include flying to Japan to play golf, rigging a game of football against a rival army team and subjecting their priggish superiors, Major Frank Burns (Robert Duvall) and Major "Hot Lips" Houlihan (Sally Kellerman), to all manner of hilarious indignities.
With its bracing mixture of chaos, carnage, and craziness, Altman's black comedy perfectly expressed the anarchic, rebellious spirit of the 1970s with its blistering anti-war message and contempt for authority. It also introduced an astonished world to the director's free-for-all, improvisational style of film-making.
Altman went on to develop this style in such genre-busting works as "Nashville" and "McCabe and Mrs Miller", while "M*A*S*H" became a long-running and massively successful TV show with Alan Alda as Hawkeye, Loretta Swit as Hot Lips and Gary Burghoff reprising his role as Radar O'Reilly.
For many, though, the original is the best - though it is ironic that another war movie, the flag-waving biopic "Patton", won that year's Academy Award for best picture.