The Bear's Den Info Files: ARC? Arc? Ark?

Aside from sounding like Popeye's laugh, There are differences.
Ark: well, ask Noah, or Indiana Jones...
Arc: part of the circumference of a circle OR in book terms, the general story line of a book or series of books.
And then there's ARC, what I really wanted to discuss:
An advance copy, also known as an advance reading copy or ARC, is a copy of a book released by its publisher before the book has gone to press for a complete printing.  ARCs are normally distributed to reviewers, bookstores, magazines, and (in some cases) libraries in limited quantities and as such are rarer than an actual 1st edition. They can be highly collectible in some cases, as they often are printed with no cover art:

and in rare cases with cover art different from that of the actual mass publication 1st edition:

Abuse of Power ARC

Abuse Of Power 1st Ed HC