An author who doesn't want their authorship known will use a Pen Name. An author who wants everyone to know they don't want their authorship known will use Anonymous, or a pen name that very obviously presents itself as a pen name.
This is done to convey the impression — which may even be true — that the author would be in trouble were his or her identity known. So it's often done with controversial works, or works that wish to present themselves as such, and with exposes.
- The Wotch by Anne Onymous.
- Primary Colors by Anonymous. Fifteen years later, "O" by Anonymous.
- Also by Anonymous The Book With No Name.
- A Prussian nobleman wrote plays under the name J.E. Mand — jemand is German for "someone."
- Go Ask Alice... allegedly.
- The Bride Stripped Bare. Australian Nikki Gemmell eventually revealed her authorship.
- The Name Of This Book Is Secret and its sequels by Pseudonymous Bosch, although it's pretty much confirmed by now that he's author Raphael Simon.
- Frankenstein, on its initial publication, to hide that the author was a young woman.
- During her lifetime, Jane Austen's novels only identified the author with the words "By a Lady".
- Nearly all creators of the Visual Novel Katawa Shoujo use nicknames (e.g. cpl_crud, silentcook, Aura)
- Many of the credits in Mega Man II are aliases, e.g. Inafking, Tom Pon, 2m03cm Man, Yuukichan's Papa, Fish Man)
- Marvel Comics:
- Brotherhood, about the Brotherhood of Evil Mutants, was apparently written by "X". Popular opinion has it that this was Howard Mackie, but the truth has never been revealed.
- The Generic Comic Book is credited to "An Author, a Pencilist, an Inker, a Colorist and a Letterist."
- The Federalist Papers was published under with the pseudonym "Publius". The papers were drafted in response to the Anti-Federalist Papers, a series of parallel essays, published under the pseudonyms "Cato", "Brutus", "Centinel", and "Federal Farmer".
- Vox and King Beau is a Creepypasta originally posted on /x/ that takes the format of a young woman named Vox who posts on /x/ looking for advice. The author of the story never goes by anything other than Vox or hints to the story being fictional at all.
- cool and new web comic is a parody of Homestuck by an author known as "o". There are many theories as to who the author is, to the point that the very mystery of his identity is a meme.