J. K. Rowling spoke on 2 November 2015 on NPR’s Morning Edition about her decision to adopt the nom de plume Robert Galbraith for her detective novels.

Why do people use pen names? Modern practice tends to fall into the J. K. Rowling mode: for different genres an author may adopt a different name. (J.K.Rowling recently confirmed that she is writing a new children’s book under her own name.) Any real concealment is usually short-lived, and many authors happily continue to do it while admitting the fact on their title pages — e.g. “Ruth Rendell writing as Barbara Vine”. Originally it tended to happen for more serious reasons: if you were writing subversive stuff, disguising your name, like Martin Marprelate, could be an important step to avoiding jail-time. In the early nineteenth century it became a bit of a trend for lady authors to adopt a male nom de plume. Mary Anne Evans became George Eliot, Amandine Lucie Aurore Dupin became George Sand, and the Brontë sisters became Acton, Currer and Ellis Bell. I wonder why we still know the others by their pseudonyms while the Brontës have come out? The Conversation discusses women’s use of male-sounding pseudonyms, and here, from Publishers Weekly, is a male writer discussing his decision to use his grandmother’s name as his nom de plume for his latest novel.

Personally, although I cannot claim any pseudonymous work, I think part of the reason for assuming an identity when writing is that it distances you a bit from the material. For some it may free them up to say things which their up-tight real persona would never disclose. I have observed that I can be considerably more outspoken in German for instance than I’d ever be in English, where my discourse is freighted by years of upbringing and tight regulation. Perhaps some writers have been similarly afflicted and have found relief by speaking as some alter ego. And then of course there’s the fear that if your book is a wild success people will never leave you alone, constantly begging for autographs and loans. Not everyone wants to be a star.

Françoise Sagan (Quoirez) isn’t included in Wikipedia’s rather stultifying list of pen names, as no doubt are many others too boring to mention. Stan Lee is: the comics king began life a Stanley Martin Lieber, and has just published an autobiography appropriately with lots of pictures. Fans of The Big Bang Theory will want to know that he was on NPR talking about it recently. Ellery Queen is a collective pseudonym, concealing behind it two authors, Frederic Dannay and Manfred Lee. Edward Pygge appears to have been hogged by five different poets. Enough.