Buster Keaton was born with the movies in 1895. He learned his timing and honed his comic instincts in vaudeville, beginning at age 5 as the youngest member of the Three Keatons.
His parents, Joe and Myra, used their child as a prop; he was, his biographer Jeffrey Vance writes, "routinely thrown about the stage, and occasionally into the audience, by his irascible father."
For anyone who delights in cinematic sight gags, silents are golden. Whether it was Harold Lloyd dangling from a clock, or Charlie Chaplin spinning on roller skates, or Lillian Gish on an ice floe, actors soon developed an eloquence that needed no words, and few matched the majestically stony countenance of Buster Keaton.
What needs to be said as Keaton opens a newspaper that unfolds and unfolds until it is the size of a bedsheet and envelops him in "The High Sign," or as he spills a bottle of glue on his counter in "The Haunted House," or as he does a swan dive, in "Hard Luck," into the cement next to the pool, leaving a large hole? The visual punch lines speak for themselves.
There was, in fact, no use for dialogue in any of the 45 two-reel and feature silent films he made starting with "The Butcher Boy" in 1917 and ending with "Steamboat Bill, Jr." in 1928.
The advent of talking pictures in 1927 ruined the careers of many actors who looked great mouthing dialogue but had terrible delivery or accents. The problem for Keaton after the silent era was not his voice but rather the studios' insistence that virtually every second of talkies have somebody saying something, regardless of whether it advanced the story. In Keaton's case, words failed him. Nothing was as articulate as his carefully planned pratfalls.
Although Keaton worked almost steadily until his death in 1966, none of his performances in those ensuing 40 years match the incandescence of his early work. Many of the half a dozen MGM films that Keaton made in the 1930s were his greatest commercial successes, but the studio clearly didn't know how to transfer the silent specialness of Keaton to talkies. In his early films, Keaton was a controlled improviser. MGM turned him into a scripted comic, and he disliked these pictures because they came at the expense of comedy and at the promotion of farce.
[Updated Oct 28, 2010: An earlier version said Keaton's death was in 1968, he died in 1966.]