A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects.—Lazarus Long
Widely considered one of the most influential and iconic writers of Sci Fi and Speculative Fiction of the Twentieth Century. He is counted as one of the "Big Three" of Science Fiction along with Arthur C. Clarke and Isaac Asimov. Often the standard to which other Science Fiction writers are compared, although he caught considerable flak for some of his recurring philosophical and political themes. His works range from space adventure YA novels to political manifestos, and generally score towards the "hard" side of Mohs Scale of Science Fiction Hardness.
Heinlein's most notorious and most dividing novel is Stranger in A Strange Land, an Author Tract which contributed hugely to the rise of the hippie movement. However, he's probably best known with the general public for penning Starship Troopers, which was very, very loosely adapted into a film.
Rare exceptions aside, nearly all of his characters are prodigies and geniuses, to the point where this can be considered his authorial trademark.
Works by Robert A. Heinlein with their own Trope pages include:
- "All You Zombies"
- "And He Built a Crooked House"
- The Cat Who Walks Through Walls
- Double Star
- For Us the Living A Comedy of Customs
- Glory Road
- Have Space Suit Will Travel
- I Will Fear No Evil
- Magic, Inc.
- The Moon Is a Harsh Mistress
- The Number of the Beast
- The Puppet Masters
- The Rolling Stones
- Space Cadet
- Starship Troopers
- Stranger in A Strange Land
- Time Enough for Love
- To Sail Beyond the Sunset
Heinlein has probably written -- and in some cases created -- every major form of story in Science Fiction, including:
- Revolution and its aftermath (The Moon Is a Harsh Mistress and the first part of its sorta-sequel The Cat Who Walks Through Walls, If This Goes On..., later packaged in the collection Revolt in 2100)
- Organized crime invading an industry (Magic, Inc., Let There Be Light)
- Space travel (The Rolling Stones along with most of his short stories)
- Time Travel and Paradoxes ("By His Bootstraps", "All You Zombies", Time Enough for Love, The Door Into Summer)
- The Multiverse and cross-universe travel (The Number of the Beast, Glory Road)
- Age extension and immortality (Methuselah's Children, Time Enough for Love, The Moon Is a Harsh Mistress)
- Labor strikes by people critical to the economy ("The Roads Must Roll")
- Crabby old man has brain transplanted into gorgeous woman (I Will Fear No Evil)
- Generation Ships; Society on a self-contained spaceship forming its own religious mythos (Orphans of the Sky/Universe)
- Problems of precognition and knowing the future ("Life-Line")
- War and the government it creates (Starship Troopers, frequently considered one of the best military novels ever written)
- Slavery, freedom, and the forms each can take (Citizen of the Galaxy)
- Settling on and civilizing new and unfamiliar worlds (Farmer in the Sky, Tunnel in the Sky)
- Human-alien relations (Red Planet, Have Space Suit - Will Travel, Space Cadet, Double Star, Starman Jones, The Star Beast, Stranger in A Strange Land).
- The transformative power of innocence plus observations of humanity from an Outsider (Stranger in A Strange Land)
- The idea of fiction creating worlds (The Number of the Beast and its sequels)
- The idea of heaven not being heaven without your loved ones. (Job: A Comedy of Justice)
Heinlein's protagonists are typically geniuses, often with perfect memory and a love for mathematics. They have held opinions covering most of the political spectrum, to the point where the oft-made argument "Heinlein's heroes all have his political opinions!" needs to account for the fact that the sum total of "political opinions held by Heinlein protagonists" includes many mutually contradictory ideas. For that matter, Heinlein himself expounded the merits of wildly different political opinions; several of his earliest books were essentially guided tours through a couple of (non-Marxist) anarcho-socialist future paradises -- though said paradises also valued sexual freedom and the right to bear arms. He would later write of a yet another such (alien) paradise in his (in)famous Author Tract Stranger in A Strange Land -- and he would reference said paradise throughout much of his future work.
His protagonists can be expected to believe in sexual freedom, the right to bear arms, the death penalty, and private ownership and private enterprise, and to not be shy in expounding on those beliefs. Most believe in hard work and although they often suffer bad luck, in the end it pays off for them. Humans Are Special, a fact often expounded upon by his heroes, who are often, by birthright, training, or sheer openmindedness even "specialer" than regular humans. They also tend to be ridiculously smart. This has lead to some (not always unwarranted) accusations of Sueism in Heinlein's writing.  Expect there to be at least one foolish and lazy person to contrast to the heroes. However, smart lazy people are usually respected -- see "The Tale of The Man Who Was Too Lazy To Fail" in Time Enough For Love. (Usually, but not always. In The Puppet Masters, the main characters praised engineers but disdained scientists, as the latter merely sit around making up theories without actually building anything.)
Mutual respect and personal autonomy are key themes, and Polyamory is presented as the most rational and reasonable form of partnership. It's also not uncommon for Heinlein's heroes to explore the idea of incest -- in any case, family bonds are always very strong. Education (particularly math and linguistics) is a vital (but personal and freely chosen) process, and on occasion there are allusions to naive forms of chaos magic (i.e. mankind's ability to manipulate nature simply by being clever).
In addition to that, throwing rocks at people who don't agree with one's personal beliefs is quite okay when one's personal beliefs are enlightened enough -- although Heinlein's heroes tend to bluff rather than use lethal violence. Racism is also always rejected. Heinlein was indirect about it, but many (if not most) of his main characters are implied to be multiracial or at least not white.
His later books valued individual autonomy much more than the earlier ones, and his opinion of government, politics, and politicians changed accordingly. By the end, his opinion appeared to be that there are two types of politician: the Wide-Eyed Idealist who can't be trusted because anyone who can convince him it's for the greater good will get him to abandon a promise, and the Corrupt Politician who can be trusted because he knows he has a reputation to maintain as someone worth buying.
Heinlein's stories are populated by certain stock characters:
- The Genius Child: A very common character both in Heinlein's YA novels and in his political work. The genius child is often completely unaware that he or she is a prodigy, and simply dreams of going into space and having wild space adventures. Some of these characters, however, fully know how smart they are, and learn an important lesson about humility. Knowing next to nothing about interstellar politics, they tend to wise up by the end of the story and accept responsibility for their actions. Kip, Max, Peewee, and the twins Cas and Pol embody this, and Valentine Michael Smith is this character type taken to its logical extreme.
- The Competent Man (sometimes woman): Essentially your classic leading man character, he or she is competent in a reasonably wide range of fields (usually including several languages, sciences and/or technologies), and usually is also The Man (or Woman) Who Learns Better, having learned an important lesson and experienced considerable personal growth by the end of the story. The latter aspect is more prominent in Heinlein's juveniles. This can also be an adult version of the Genius Child who already knows how to deal with adult life, or simply the Genius Child's close friend.
- The Wise Old Mentor (usually, but not always, male): Professor Bernardo de la Paz, Hazel Meade Stone, Joseph Bonforte, Jubal Harshaw, and of course Lazarus Long, who also falls into the above category.
- The Gorgeous Woman: Spirited, beautiful and complex. Many of them have red hair, like Heinlein's wife Virginia. In fact, it is often tempting to assume the Gorgeous Woman is essentially Virginia in various guises. Star, in Glory Road, is described as hundreds of women in one body, along with a number of men, and amply describes the more universal version of the character.
These characters are best seen in The Puppet Masters, which is also his Alien Invasion plot.
His characters are often very intelligent, highly skilled (or they quickly learn any skills needed), good at math, and sometimes without major mental or physical defect. On this last qualification, there are notable exceptions:
- Waldo, a physical and emotional cripple in need of redemption.
- Oscar Gordon, a self-described grunt with a prominent facial scar, whose genius mainly lies in forms of violence and the practical application of personal ethics. After serving his time in the military, he gets recruited from an endless beach vacation by Star.
- Juan Rico, another grunt, who doesn't have the stuff to join one of the more glamorous organizations but proves to be an above-average officer and the right man at the right time. In film adaptations they tend to forget he's only called "Johnny," not named that.
The ProtagonistEvery character of All You Zombies, a heartless cad with an intersexual condition (and time machine).
- Manuel Garcia O'Kelly "Mannie" Davis, a one-armed computer engineer (lost the other arm in an accident), who is otherwise the Archetype for a technically competent hero.
- While Roger Stone is a Competent Man, he freely admits that he's the least intelligent and adaptable person in his entire family, not to mention one of the least so among Heinlein's roster of Competent Men. He yet is the successful leader and moral conscience of the entire Stone family, and is perhaps the only being in the entire multiverse that Heinlein has written winning an argument with Hazel Stone.
- Hugh Farnham in Farnham's Freehold is not extensively educated or much more intelligent than the norm and his mathematical abilities are unknown, but he does have access to a long list of useful books, which come in handy when he becomes a freeholder.
- Podkayne Fries in Podkayne of Mars is a naive and optimistic 16-year-old girl who isn't really capable of understanding evil, and thus can't quite comprehend the villains or the seriousness of the political drama in the midst of which she finds herself.
- Podkayne's brother Clark, who in contrast is a sociopathic PreTeen Genius only barely kept in check by his affection for his older sister -- and who is only redeemed by Poddy's (near)-death as a result of the plots in which they've become entangled.
- Valentine Michael Smith is a human raised on Mars who is intelligent but with No Social Skills (but later becomes a charismatic preacher)). Apparently Heinlein had a bet going with L. Ron Hubbard to see which one could inspire a cult... Heinlein lost, nanu-nanu. (But many people grok that it was a close race for a while there).
- While not a main character, the Boss (the mentor/competent man archetype) of Friday is a one-eyed cripple, and apparently a former resident of Luna. Friday herself is neurotically insecure as a result of her upbringing.
Heinlein's most notable protagonist is Lazarus Long, a near-immortal rogue and Anti-Hero. Lazarus Long appears across much of Heinlein's work, often being both the Competent Man and the Wise Old Man. He is a strong proponent of the atheistic, Libertarian, Free-Love Future worldview that became a trademark of Heinlein's work, and is a frequent target of criticism for being a Marty Stu and Author Avatar.
Heinlein's approach to female characterization is sometimes controversial. While his female characters are a reasonably varied lot, they tend to have a few things in common: The men spend a lot of time explaining things to them. They rarely end the story un-paired with a man, sometimes even expressing a fear of lesbianism. And they often see motherhood as their highest goal. Many stories feature underage (barely teen-age) girls "bundling" with far older men. It should be considered, however, that at the time he wrote most of his novels an actively dominant female character was an extreme rarity.
Heinlein's adult years were during the Cold War, and he was extremely hawkish, believing that the Soviets were a serious threat to the US, and that a strong military with lots of nuclear missiles was the only sane response. (For example, one of his character regarded the difference between the Soviets and mind-controlling alien slugs as nearly irrelevant). Though his views were not uncommon at the time, given that the Soviet Union folded shortly after Heinlein's death, understanding his Soviet-phobia can be difficult for modern readers but necessary to understanding his work. (Claiming the genocidal hive-minded Bugs from Starship Troopers are stand-ins for the Soviets is not a stretch).
He also invented and explored the concept of Pantheistic Solipsism in his later works, also known as the "World as Myth" philosophy: where powerful writers create universes via the act of writing. He uses this for multiple Crossovers between world lines, including at least one meeting between every major hero he created in a single scene. It's also noted that later characters would call him (as the author) out for the horrible actions his characters suffer if this idea is true.
His impact can be best seen in Larry Niven's short story The Return of William Proxmire where a fictional version of the infamously Luddite U.S. Senator Proxmire -- who wishes to prevent the "waste" of the space program -- decides to use time travel to cure Heinlein's pulmonary tuberculosis because every scientist and engineer "fanatic" in the space program credits him as being their inspiration. (For the interested, curing Heinlein means he rises to prominence in the Navy and pays attention in 1940 when Goddard tries to warn the military about the potential and dangers of rockets. When Proxmire returns to the present, Admiral Heinlein's Navy-run program has set up lunar colonies, orbital solar power stations, and prevented the Russians from developing ICBMs).