Robert Anson Heinlein (July 7, 1907 - May 8, 1988) was one of the most influential authors in the science fiction genre. He developed new themes, new techniques and approaches. He became the first science fiction writer to break into major general magazines in the 1940s and 1950s with true, undisguised science fiction, and the first bestselling novel-length science fiction in the 1960s.
After high school, Heinlein attended the U.S. Naval Academy in Annapolis, Maryland. After graduating from the Academy in 1929, he served as an officer in the United States Navy until 1934, when he was discharged due to pulmonary tuberculosis. During his recovery he re-invented the waterbed. The military was the second great influence on Heinlein; throughout his life, he strongly believed in loyalty, leadership, and other military ideals. This attitude permeated his fiction, most prominently (and controversially) in the novel Starship Troopers. His 1961 Stranger in a Strange Land was the first science-fiction book to become a national best-seller -- readers who as a rule did not read SF books were interested in Heinlein's philosophy, as expressed in that novel, which transcended what was seen as the usual scope of such novels at the time, preoccupied with robots, flying saucers, and bug-eyed monsters.
After his discharge, Heinlein studied mathematics and physics at the University of California, Los Angeles. He also worked in a series of odd jobs, including real estate dealership and silver mining. Heinlein was active in Upton Sinclair's socialist EPIC (End Poverty In California) movement in early 1930's California. When Sinclair gained the Democratic nomination for governor of California in 1934, Heinlein worked actively for the campaign (which was unsuccessful). Heinlein himself ran for the California state assembly in 1938, which also was unsuccessful (an unfortunate juxtaposition of events had Konrad Henlein making headlines in the Sudetenlands). While not destitute after the campaign -- Heinlein had a small disability pension from the Navy -- he turned to writing to pay off his mortgage, and in 1939 his first story, "Life-Line", was published in Astounding Magazine. He was planning on retiring as soon as he held his mortgage party, but wanted a new car, a trip to NY, and a few other things. He then told John Campbell, the editor of Astounding, that he was planning to quit. He made an agreement to send a few stories he had on tap but that he would quit writing when Campbell bounced a story. When Campbell bounced a story, he quit and started to feel unwell. He became jittery and absent-minded, suffered loss of appetite, weight loss, and insomnia. He thought this might be the onset of a third attack of pulmonary tuberculosis. Campbell eventually dropped him a note, and when reminded of the conditions, said he would take another look at the story. He did so and asked for some very minor edits. When Heinlein sat down to do those edits, he suddenly felt better.
During WWII he served with the Navy in aeronautical engineering, after the war he returned to writing. During his time there, he recruited a young Isaac Asimov to work at Mustin Field, where he wrote the first two books of the Foundation Trilogy. He also got L. Sprague de Camp yanked from the naval commission he was headed for, to work there as well.
In the early 1970s, Heinlein suffered a series of strokes. Heinlein credited his recovery to the support of his wife Virginia and improved medical technology that he saw as "spinoff" from space technology. He went on to write several more bestsellers.
In his book To Sail Beyond the Sunset, Heinlein has the main character, Maureen, state that the purpose of metaphysics is to ask questions: Why are we here? Where are we going after we die? (and so on), and that you are not allowed to answer the questions. Asking the questions is the point for metaphysics, but answering them is not, because once you answer them, you cross the line into religion.
Maureen doesn't state a reason for this; she simply remarks that such questions are "beautiful" but lack answers. The implication seems to be as follows: because (as Heinlein held) deductive reasoning is strictly tautological (i.e. never generates conclusions that were not already presumed in the premises) and because inductive reasoning is always subject to doubt, the only source of reliable "answers" to such questions is direct experience -- which we don't have.
Maureen's son/lover Lazarus Long makes a related remark in Time Enough For Love. In order for us to answer the "big questions" about the universe, Lazarus states at one point, it would be necessary to stand outside the universe. (It is not quite clear why this should be so, but at any rate this is what Lazarus says. The usual warnings about mistaking a character's views for those of the author apply here, of course, but this opinion seems fairly easy to tie into Heinlein's own views as expressed in nonfiction and interviews.)
During the 1930s and 1940s, Heinlein was deeply interested in Count Alfred Korzybski's General Semantics and attended a number of seminars on the subject. His views on epistemology seem to have flowed from that interest, and (some of) his fictional characters continue to express Korzybskian views to the very end of his writing career.
Other recurring themes binding Heinlein's works together include individual dignity, the value of both personal liberty and responsibility, the virtue of independence, science as a liberating factor, the perniciousness of bureaucrats, the brutality of corporate power, the hypocrisy of organized religion, the objective value of Korzybski's general-semantics and the subjective value of mysticism.
Heinlein originally wrote his first book, Rocket Ship Galileo, because a boy's book was solicited by a major publisher. The publisher rejected it because 'a trip to the moon was preposterous'. He took the manuscript to Scribner's, who bought it - and started a chain of options resulting in a yearly Christmas trade book. This agreement lasted for twelve years, until the editor (who hated science fiction) rejected a manuscript, which Heinlein then took across the street and for which he later won a Hugo.
The novels that he wrote for a young audience are very different than his "adult" works. He is still the same person, but the themes he takes on in these books have much more to do with the kinds of problems that adolescents experience. His protagonists are usually very intelligent teenagers who have to make a way in the "adult" society they see around them. They are simple tales of adventure, achievement, dealing with dumb teachers and jealous peers. The books "Have Space Suit, Will Travel", "Farmer in the Sky", "The Rolling Stones" are most representative of this type.
However, Heinlein was outspoken with editors and publishers (and other writers) on the notion that juvenile readers were far more sophisticated and able to handle complex or difficult themes better than most people realized. Thus even his juvenile stories often had a maturity to them that make them readable for adults. Indeed, his last "juvenile" novel was Starship Troopers, which is also probably his most controversial work. Starship Troopers was written in response to unilaterally stopping nuclear testing.