''Definitely Maybe'' (''За миллиард лет до конца света'', literally ''A Billion Years Before the End of the World'') is a short 1974 novel by the Creator/StrugatskyBrothers about the nature of scientific progress.

An astrophysicist, Dmitry Alekseevich Malyanov, is working on his thesis on stellar interaction in his apartment, when strange events start happening. An attractive woman apparently sent by his wife arrives, people who have never been interested in astrophysics start probing him about his work, and he's visited by unpleasantly insistent government investigators. What do all of these events mean?

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!! Definitely Maybe contains examples of:
* AncientConspiracy: The Order of Nine [[spoiler: which turns out to be one of the many disguises of the Laws of Entropy.]]
* TheBadGuyWins: Pretty much what happens in the story. [[spoiler: Laws of Entropy got everyone besides Vecherovsky (whom they will likely crush as well) to abandon their work and didn’t sustain any damage in process.]] On the other hand, [[spoiler: it’s debatable how much of a bad guy they really are.]]
* DownerEnding: Most people will probably see the end of the story as this. [[spoiler: Malyanov and his friends have been forced to abandon the work on the certainly Nobel-winning prizes, all of them are likely to be mentally scarred for life, Zakhar now has his illegitimate child to take care of and Vecherovsky is very likely to get killed for carrying on.]] On the other hand, [[spoiler: Weingarten will get to be the head of an advanced research center as a consolation prize, all of them are alive for now and Zakhar might yet reconnect with the child’s mother, or become a better person through the parental responsibilities.]], so it’s not all bad.
* TheCasanova: Zakhar.
* CreepyChild: [[spoiler: Zakhar's illegitimate son.]]
* DrivenToSuicide: Malyanov’s neighbour, Snegovoi. His death early on is used by [[spoiler: the Laws of Entropy]] to threaten Malyanov with prison sentence.
* EldritchAbomination: [[spoiler: Laws of Entropy]] fit pretty well under the definition, although they’re arguably one of the milder forms.
* MoodWhiplash: Many of the [[spoiler: Zakhar’s son’s]] lines have almost nothing to do with the events at hand and do a lot to lighten the mood.
* LampshadeHanging: Vecherovsky does this in regards to standard sci-fi/conspiracy tropes, pointing out that neither the alien civilisation nor the ancient conspiracies would be so inconsistent in their efforts against them. The conclusion? [[spoiler: Their adversary is not sentient and thus doesn’t think logically.]]
* ForScience: Vecherovsky takes this approach to [[spoiler: Laws of Entropy]] at the end of the story, believing that since it is ultimately [[spoiler: a mindless force of nature, it has to obey constants and laws like gravity or strong nuclear force]], and thus he can figure out the way it works. The novel ends before we find out whether or not he will succeed.
* RandomEventsPlot
* RunningGag: The joke about two roosters.
* TheStoic: Vecherovsky, who managed to remain calm throughout the whole ordeal and is [[spoiler: the only one who is still resisting laws of entropy by the end.]]
* UnwantedHarem: Zakhar Gubar is more or less gang-raped by his mind-controlled exes.
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