From "About the Author" in A Game of Thrones:

GEORGE R. R. MARTIN sold his first story in 1971 and has been writing professionally since then. He spent ten years in Hollywood as a writer-producer, working on The Twilight Zone, Beauty and the Beast, and various feature films and television pilots that were never made. In the mid '90s he returned to prose, his first love, and began work on his epic fantasy series, A Song of Ice and Fire. He has been in the Seven Kingdoms ever since. Whenever he’s allowed to leave, he returns to Santa Fe, New Mexico, where he lives with the lovely Parris, a big white dog called Mischa, and two cats named Augustus and Caligula, who think they run the place.