Short answers, pulled from the story.
Hilary Whitehall Putnam arrived in the world on the 31st of July 1926, within a hospital in Chicago, Illinois. His family moved to France just six months after he was born before returning to the United States in 1933.
The Twin Earth thought experiment demonstrated that meaning depends on factors outside the mind rather than internal states alone. Putnam concluded that meaning just ain't in the head by showing how identical physical states can carry different meanings based on external causal history.
Putnam contributed significantly to Hilbert's tenth problem which was settled by Yuri Matiyasevich in 1970 through his earlier research with Julia Robinson and Martin Davis. This work provided essential groundwork for the final proof while establishing mathematical entities as indispensable for science.
Putnam used the brain-in-a-vat scenario to challenge global skepticism regarding knowledge claims and target metaphysical realism which assumes a gap between conception and reality. He argued that if one were actually a brain in a vat, the claim would be incoherent because words refer to kinds experienced by ancestors or users.
Hilary Putnam organized one of MIT's first faculty and student anti-war committees in 1963 and became an active opponent of the Vietnam War while teaching at Princeton University. He joined the Progressive Labor Party as an official faculty advisor to Students for a Democratic Society in 1968 before permanently severing his relationship with the PLP in 1972.