- J.K. Rowling (Robert Galbraith)
- Joe Klein (Anonymous)
- Nora Roberts (J.D. Robb)
- Ruth Rendell (Barbara Vine)
- Anne Rice (Anne Rampling, A.N. Roquelaure)
- Jayne Anne Krentz (Amanda Quick, Jayne Castle)
- Stephen King (Richard Bachman)
- Evan Hunter (Ed McBain)
- Louisa May Alcott (A.M. Barnard)
- Charlotte, Emily and Anne Brontë (Currer, Ellis, and Acton Bell)
IIRC it was Amazon who first revealed the true name, and the newspaper merely reported it. Not that Amazon has any vested interest....
John Camp has written many books as John Sandford. What he published under his own name was unsuccessful so he quit and continued as the successful author, John Sandford.
And I'm surprised that you forgot to mention Baroness Amantine Dudevant who wrote as George Sand.
The pseudonyms for Anne Rice and Jayne Anne Krentz have also never really been secret. Krentz chose different pen names for different genres/subgenres. Readers know her contemporary stories are as JAK, that her historicals are as Amanda Quick, etc.
This list is not complete without including LAURA ALBERT, who wrote three critically acclaimed novels, SARAH, THE HEART IS DECEITFUL ABOVE ALL THINGS, and HAROLD'S END under her pseudonym, J.T. LeROY. Additionally, she was included in anthologies, and authored well-received articles and reviews in major magazine publications from 1997 - 2005.
I believe Romain Gary has its place on this list. He won two Goncourt prize. One with its real name Romain Gary and the other one with his pseudonym Émile Ajar.