Following For A Few Dollars More, which added Lee Van Cleef to Eastwood, the culmination of Leone's "dollars" trilogy tosses in Eli Wallach as a third party and sets the almost-comic eternal struggles of the three protagonists as they try to make a dishonest living in the Wild West against the wider insanity of the American Civil War.
Actually a prequel to the earlier Westerns (we see Eastwood gradually acquiring the clothes he wears in the other films), this is wonderfully wry, stylish and violent, shot through with a compassion perhaps lacking in the tougher pictures but still heavy on massacres, battles, hangings, gunfights and operatic slaughter.
After this, Leone and Eastwood went their separate ways: Leone to even more epic visions (Once Upon A Time In The West, Once Upon A Time In America) and Eastwood to Hollywood superstardom and an ever-evolving directorial career.