This is becoming, more and more, a common practice. Charlaine Harris wrote mysteries, but when she decided to add werewolves and other paranormal beings, she became shelved in both romance and mystery. Go figure! Dean Koontz, best known as a horror writer, includes elements of suspense, thriller, and throws in some science fiction.
Other writers keep the genres separate, but write in several. Beth Groundwater writers mystery and science fiction, keeping both forms pure.
Some cross genre works have acquired their own names, dark fantasy for fantasy and horror, science fiction westerns and even space westerns. Science fiction western has given birth to the more current steampunk, a quickly growing genre all its own.
Steve Metze, Mary Ann Loesch, and I are three writers who write in different genre, but decided to put our stories together anyway and get an anthology published. So we did! All Things Dark and Dastardly contains elements of mystery, horror, paranormal, fantasy, science fiction, and maybe some others. Sometimes I'm not sure where a genre begins and ends. I, myself, contributed mystery and paranormal here, but have recently branched out into horror and even wrote a zombie story that's being submitted. I can detect mystery in most of my stories, but it may be hard for some readers.
As Mary Ann pointed out on a recent guest blog for Rasana Atreya, our common thread is darkness. The three of us seem to have twisted little minds and like it that way. If you like your stories dark and dastardly, keep watch here for our release in October.
We're excited about this volume and hope you will be, too!