First time I ever heard of them. I looked them up, and they appear to be an imprint of Simon & Shuster, with a fair number of books about reincarnation and other new wave tripe.
Here's the web site:
http://www.simonsays.com/content/destination.cfm?sid=33&pid=427719
Oh, and I can't resist quoting their explanation of their origins from the web page:
"With a growing Pocket Books hardcover list and the successful publishing of such books as Jennifer Lauck's Blackbird, Jennifer Weiner's Good In Bed, and Shanghai Baby by Wei Hui, came the founding, ... "
Yeah, Atria is an imprint. There are a lot of those imprints running around. I could've told you right off the bat on that one.