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''Double Star'' is a science fiction novel by Creator/RobertAHeinlein first published in 1956 as a serial. It's ''ThePrisonerOfZenda'' InSpace.

Lorenzo Smythe is an out of work actor. Brilliant at his trade, egotistical as hell, but ''completely'' unemployed. He receives an interesting job offer: impersonate someone so perfectly that no one will know he isn't the original. Only after accepting the job (under a little desperation) does he realize the person in question is John Joseph Bonforte, a famous (and infamous) politician who is the antithesis of every vague political opinion the generally species-bigoted Smythe holds. But he's accepted the job, and to hide Bonforte's kidnapping from the public, Smythe must learn to completely become another person in looks, thoughts, and actions--and to put aside his own.

Although Smythe is reluctant at first, he soon becomes interested in the political opinions he's now forced to advocate, and starts to make an honest effort to get along with the aliens and the political supporters he always tried to avoid in the past. And when he has to make an appearance at the court of Bonforte's long-time friend,Willem of Orange, Emperor of the Solar System, he finds himself enjoying his new role and the friendships it brings more than he'd imagined...

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!!This novel provides examples of:

* AuthorFilibuster: It wouldn't be a Heinlein novel without one. [[spoiler: Although this is one of the better ones, being a narrative from a former racist (speciesist) about how he learned the idea of common values.]]
* BecomingTheMask: [[spoiler:By the end of the novel, "Smythe" no longer exists. He ''is'' Bonforte.]]
* BlueAndOrangeMorality: Martians have a highly complex system of politeness. The main problem of the book is that a politician may be late to a ceremony that inducts him into a Martian clan. There is a legend on Mars about a young Martian who was on his way to a high honor (equal at least to an alien being inducted to a clan), and the consequence of being late was ''death''. Due to no fault of his own, he was late, but it was proposed (by some of the Martian radicals) that he be given a second chance, on account of youth and having an extremely distinguished record. He would have none of it. So he insisted on the right to prosecute the case against ''himself'', won the case, and was consequently executed. Which is why he is now held in reverence as the ''patron saint of propriety'' on Mars.
* BluffTheImpostor: The Emperor figures out Smythe is not Bonforte when he agrees to play with his toy trains. Bonforte and the Emperor had a friendly in joke between them: the Emperor would always invite him to play trains and Bonforte would always refuse and make fun of his hobby.
* {{Fainting}}: when Smythe's cover is nearly blown Penny manages to hold herself together until they reach the privacy of her office whereupon she faints. Later, after a day of agonizing tension, she discovers their ploy has not been blown and faints again from relief.
* FictionalPoliticalParty: The plot revolves around the struggle between the Humanity Party (with the slogan "government of humans, by humans, for humans") and Bonforte's Expansionists. Smythe is at first confused by reading that the early Expansionist Party sounds a lot like the present Humanity Party (which splintered off as the Expansionist coalition became less Terracentric). He didn't realize at first that "parties, like men, change as they grow up."
* LostInCharacter: Smythe is hired to impersonate a kidnapped politician. He becomes so immersed in being this man that [[spoiler: after the original is killed, he takes over and actually becomes him. By the end of the book, he's happily abandoned his old life. What's more, his secretary has convinced herself that she never loved anyone but Smythe, and Smythe doesn't really mind the fact that she's obviously lying to herself by forgetting the original man.]]
* MethodActing: Smythe uses some amount of this to get into his characters, and even used the psychotic aspect of one character as a crutch when he had to [[spoiler: chop up a body.]]
* NoodleIncident: Smythe has many of these in his background:
-->"He mentioned a couple of details in my past that I would have sworn were buried and forgotten. All right, so I did have a couple of routines useful for stag shows that are not for the family trade a man has to eat. But that matter about Bebe; that was hardly fair, for I certainly had not known she was under age. As for that hotel bill, while it is true that bilking an 'innkeeper' in Miami Beach carries much the same punishment as armed robbery elsewhere, it is a very provincial attitude I would have paid it if I had had the money. As for that unfortunate incident in Seattle well, what I am trying to say is that Dak did know an amazing amount about my background but he had the wrong slant on most of it."
* ThePowerOfActing: Smythe's acting skills are all that stands between Human and Martian relations completely falling apart.
* RailEnthusiast: The Emperor.
* SecretIdentityIdentity: When [[spoiler:Bonforte dies]], Smythe must choose between his own identity, and the greater good.
* ShoutOut: See the NoodleIncident entry. The bit about "I didn't know how old she was" is about ErrolFlynn.
* SmallNameBigEgo: Smythe, especially early on in the novel. He's entirely convinced that he's one of the finest names in theater, and his lack of recognition is mostly a case of rotten luck. At the end of the novel, when he looks back at how he was before the events of the novel took place, he can't believe the bloated sense of self worth he used to have.
** To be fair he is clearly a very fine actor, and the Emperor himself is one of his fans.
* SnowballLie: The basis of the entire novel.
* SpottingTheThread: Smythe spends weeks studying Bonforte's files on everyone around him to make the masquerade work. He notices that the file on the emperor is nearly empty, and assumes that they don't have much contact... [[spoiler: until he meets the emperor, and gets found out, because the point of the files is to help Bonforte remember things about people ''less'' politically important than he is. He's caught when he dutifully plays with the emperor's toy trains instead of teasing him about them.]]
--> [[spoiler: It was not until later that I realized that the file had not been defective, in view of the theory on which it was based, i.e. it was intended to let a famous man remember details about the less famous. But that was precisely what the Emperor was not--''less'' famous, I mean.]]
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