This is pretty major and pretty awesome. Deadline reports:

Screenwriter Charlie Kaufman is putting that cosmic mind of his toward his first book. Kaufman, whose scripts include Eternal Sunshine of the Spotless Mind, Adaptation, Confessions of a Dangerous Mind, Human Nature and Being John Malkovich, has just closed a deal for his first novel for Grand Central Publishing, I'm told. The subject of the novel is being kept under wraps. (Source)

That's all we know.

I came to Charlie's work as a reader -- I was into his scripts before I'd seen his films. I'm much more of a reader than a film-goer. For years, now, there have been rumours and suggestions that Charlie would or should try writing a novel. This is gonna be very interestin' indeed, if it happens.

Thanks to Justin!