I write under two names; I use my real name - Helen Edwards - for my non-fiction work. Helen Libby is a pseudonym, and yet it's not so far removed from my real name, being as Elizabeth is my middle name and Libby is a shortened version of Elizabeth.
So there you have it. Why do I use two names? Well, I wanted to separate my non-fiction work from my fictional stories. There is another reason though. When I began self-publishing my novelettes late last year, I spent a lot of time thinking about my author name. It became incredibly important to me to use a name that was all mine, not my married surname and not my maiden name. I went through various names, but eventually narrowed it down to Helen Libby; it just felt right. I have never regretted my choice of author name.