What's an ARC?

I will readily admit to the fact that up until about three months ago I had NO idea what an ARC was. But the answer to my question above is actually pretty simple.

ARC stands for Advance Reading Copy (though I've also seen a few variations, like Advanced Readers Copy) and basically looks like a paperback version of the hardcover first edition. A limited number are printed up, usually about six months or so before the book's release, and are then sent to reviewers, book bloggers, librarians and...