One of the founding fathers of the hard SF tradition which sees both story and society as merely a matter of effective engineering, Heinlein started writing for pulp magazines, especially Astounding, in 1939 and was a dominant influence on the field for the next forty years. His early stories--The Man who Sold the Moon and The Green Hills of Earth--are set in a "Future History" in which American society goes through radical changes and it is private enterprise that settles in space. Heinlein wrote a number of influential young adult SF books--Starman Jones, and Podakayne of Mars--which are generally freer in their handling of scientific themes than his books for adults. The right wing strain in his thinking produced a classic of McCarthyite paranoid fiction The Puppet Masters, in which the unwary are possessed by alien slugs. He achieved his major fame, not to say notoriety, with two books of the early 1960s--Starship Troopers, which, filmed satirically by Paul Verhoeven, started a whole sub-genre of militarist SF, while Stranger in a Strange Land with its free love and imaginary religions was a favourite of Charles Manson. Perhaps the best book of his later phase is The Moon is a Harsh Mistress, one of SF's more intelligent retreads of 1776 in space; the best of his earlier books is Double Star, a flip tale of impersonation and political intrigue on Mars.