Mal ,'Bushwhacked'
There's more to life than watching Buffy the Vampire Slayer! No. Really, there is! Honestly! Here's a place for Buffistas to come and discuss what it is they're reading, their favorite authors and poets. "Geez. Crack a book sometime."
I think Scott Westerfeld wrote five adult books before moving to young adult/juvenile fiction. Anyway, some of his books are shelved with the adult sf in my library, and the others are with the YA stuff. In his FAQ, he discusses why he's been writing a lot of teen stuff lately. [link]
Emma Bull wrote a YA book (The Princess and the Lord of Night), as well as her adult fantasy and sf.
Georgette Heyer wrote contemporary mysteries, historical romances (regency but also georgian), 'straight' historical fiction, and 'straight' contemporary novels.
I didn't know that about Heyer, but then I am largely Heyer-clueless. Cool. Another good example.
Madeleine L'Engle also wrote great essays and memoirs.
What about someone like E.M. Forster, who wrote fiction, but also highly respected literary criticism and the like? (I want to call it meta, but that's clearly fandom's influence.)
(I also can't be bothered to page back and see if you're looking for contemporary examples.)
Oscar Wilde wrote essays, plays, and poetry. W. B. Yeats wrote both poetry and plays. Saki (H. H. Munro) wrote short stories and novels (and while most his stories were basic contemporary fiction, some of them had horror and/or fantasy elements). Dorothy L. Sayers wrote mysteries, translated Dante, co-wrote a play (based on her mystery characters, so that may be more a change in format than a change in genre), and wrote essays.
Donald Westlake has written mysteries, caper novels, satire, science fiction, and apocalyptic fantasy under his own name. And then there's even more stuff he writes using a pseudonym.
Thomas Hardy (ptui!) wrote novels before publishing his poetry, which was what he'd wanted to do all along.
Thomas Hardy (ptui!) wrote novels before publishing his poetry, which was what he'd wanted to do all along.
Certainly an argument for going straight to what you want to do and passing on that ugly Jude the Obscure phase.
Edna St. Vincent Millay wrote plays, too.
Tolkien was a respected philology prof who wrote children's books, essays, fantasy, translations and academic writings.