
The publisher puts these out in trade paperback size, with the full color front cover image. This is the Last Chance to catch typos. This is also the copy that the publisher sends to reviewers, hoping for some advance buzz that will sell books to their target market—libraries.
Reading an ARC isn't like reading a book. There's that sword hanging over the head feeling. Miss a typo, and it's forever in the book. And they're often hard to spot. No period at the end of one sentence? Two periods 3 pages down the road (must be a 'conservation of punctuation' thing)? Quotes facing the wrong direction? You're expected to find them all.