A work so iconic, it defines the creator. And makes people forget that He Also Did (other works, which you wouldn't believe if you didn't know).
In most cases, authors that create a great work and several lesser-known works can still be associated with all of them. However, if the work is popular enough, it overshadows all other aspects of their career. In extreme cases, the work becomes synonymous with the author's name.
- George Orwell and 1984. Despite being responsible for any number of other exceptional books, the word "Orwellian" forever refers to the totalitarian, oppressive/suppressive government present in 1984; evidence for it is right here on the site. It doesn't help that his second most famous book, Animal Farm concerns almost all of the same themes. In Britain, at least, he is remembered, at least to a degree, for his journalism relating to poverty in Britain, such as The Road to Wigan Pier.
- H. P. Lovecraft is another extreme example; Lovecraftian basically means Cosmic Horror Story and/or Eldritch Abomination.
- To complete the trifecta, Niccolò Machiavelli's non-fiction essay The Prince has forever ensured that "Machiavellian" will always be a synonym for amoral behavior in the pursuit of absolute power, despite the fact that Machiavelli himself was staunchly pro-republican.
- Orson Scott Card and Ender's Game. He also wrote a bunch of sequels and several other series.
- C. S. Lewis and The Chronicles of Narnia.
- J. R. R. Tolkien and The Lord of the Rings.
- Douglas Adams and The Hitchhiker's Guide to the Galaxy.
- L. Frank Baum and The Wonderful Wizard of Oz.
- Sir Arthur Conan Doyle and the Sherlock Holmes stories, reportedly to the author's chagrin.
- A. A. Milne and Winnie-the-Pooh.
- Herman Melville wrote a whole bunch of books. You probably only know Moby-Dick.
- Mary Shelley and Frankenstein.
- J.M. Barrie and Peter Pan.
- Joseph Heller and Catch-22.
"When I read something saying I've not done anything as good as Catch-22 I'm tempted to reply, 'Who has?'" Joseph Heller
- L. Ron Hubbard and Dianetics. Battlefield Earth runs a close second.
- God and The Bible. It'd carry over for all its other authors too, but listing all those would fill up the page.
- Charles Darwin and On The Origin of Species.
- Terry Pratchett and the Discworld.
- Leopold von Sacher-Masoch and Venus in Furs.
- Hideo Kojima and Metal Gear Solid, to his annoyance.
- Bungie, despite making ground-breaking series such as Marathon and Myth, will forevermore be known as the studio that created the Halo series.
- Alpha Dream have created quite a few games over their studio's lifespan, but they're mostly known for the Mario & Luigi series.
- Game Freak and Pokémon. Also for that matter, Pokemon creator Satoshi Tajiri and artist Ken Sugimori, who are also mostly known for their work on Pokemon despite having worked on a fair few games at the company in the past.
- Core Design was a fairly prolific developer throughout the 16-bits and 32-bits era with many succcesful titles on the Amiga and Sega CD, but most will recognize the company as the original developer of the Tomb Raider series and nothing else.