Many authors choose to use a pen name. Just like actors who use a stage name, the reasons are quite varied and might include not liking their given name or the belief that a new name will make them more successful.
Often a male author will use a pen name if he chooses to write romance stories in the belief that readers will not buy romance work written by male authors. Conversely, female authors often choose to write under a male name if they are writing western or science fiction work. Even though readers are much more open these days, authors continue to believe these stereotypes.
Some authors will choose a pen name if they are afraid their work is too personal, or too controversial. A pen name seems to offer a level of safety and anonymity.
A pen name, or nom de plume, might actually be necessary - what if your given name really is Stephen King? Or Danielle Steel? Or some other easily recognized name? A pen name also helps if you are worried that family members, friends, or others might be upset and offended by what you wrote.
Established authors sometimes use a pen name to cross genres and avoid upsetting their fan bases. Another reason for using a pen name is to switch publishers; some authors will use a new name so they can quietly shop around their work. Many writers have day jobs; they are afraid if they published under their real names their bosses might find out and assume they're not working hard enough. Avoiding office gossip or ridicule is a good motivation for using a pen name, especially when writing steamy romance novels.
One of the most common reasons for an author to write using a pseudonym is because their earlier works bombed. If an author didn’t make money for a publisher the first time, he’s not likely to get a second chance. Under a pen name, an author can be reborn.
A list of just a few of the better-known pen names:
Robert Galbraith - J.K. Rowling
Anonymous - Joe Klein
J.D. Robb - Nora Roberts
Barbara Vine - Ruth Rendell
Anne Rumpling & A.N. Roquelaure - Ann Rice
Amanda Quick & Jane Castle - Anne Krentz
Richard Bachman - Stephen King
Ed McBain - Evan Hunter
A.M. Barnard - Louisa May Alcott
Currer, Ellis, & Acton Bell - Charlotte, Emily, & Anne Bronte
George Eliot - Mary Ann Evans
Mark Twain - Samuel Langhorne Clemens