I DON'T WRITE my novels under a pen-name, and I know very few writers who do. But I get asked about it frequently, which makes me wonder if, to the general public, writing fiction seems a craft so despicable that it is best performed anonymously.
The writers in my circle who do use pen-names have their reasons. One case is a husband-and-wife team who didn't want a double-byline on their books, so they created an alter-ego to stand in for the two of them. And another case is a writer who established himself in one genre and then switched to another; he didn't want to disappoint readers who might buy his books because of name recognition, expecting his previous genre.
Writers have all sorts of reasons to use pen names. Stanley Leiber believed he would one day write full-blown novels, so when he began writing comic books, he shortened his name to a nom de plume, "Stan Lee." That name became so well-known that he adopted it legally.
The author of The Sun Also Rises was originally "Ernest Hemmingway" (double "m"). That was the family name, but he didn't like the way it looked on a book cover, so he changed it to "Hemingway."
Sometimes it's the publisher's idea. Joanne Rowling created the pen-name, "J.K. Rowling" after her publisher expressed concerns that boys might not want to read her books if they knew they were written by a woman. Jo didn't have a middle name, so she adopted her grandmother's name (Katherine), and "J.K. Rowling" was born.
Then, when she switched genres and wrote The Cuckoo's Calling, Rowling adopted yet another pen-name (Robert Galbraith). But similarities in style were noted between that book and the Harry Potter series ... enough so that one English newspaper commissioned a comparison using linguistics software. It suggested an extraordinarily high probability that the author was Rowling and, when confronted with the evidence, she 'fessed up. But Rowling continues to write as "Galbraith," and predicts that eventually his titles will outnumber those in the Harry Potter series.
Many years ago, when I wrote my first book (a climbing travelogue called 20 American Peaks and Crags, now long out of print), I did so under the name "Thomas Morrisey." But these I do all of my writing under the name I'm known by to my friends: "Tom."
Would I ever use a pen name? If I made a huge genre switch, I would consider it. But other than that, my body of work is directly linked to me, and that's probably the way it will stay.