When you've managed to source nearly every edition of a book that was released, stumbling across the slightest variations is very exciting.
For years, libraries have used services that produce a hardcover binding for paperback releases in order to increase their longevity in circulation. New library bound hardcovers can occasionally be found on Amazon, but for the most part, these enter the marketplace as library discards, but considering how most collectors feel about library discards in general, the bulk are likely sent off to landfills, or to foreign countries (where a surprising number of unsold books are donated).
This copy is in surprisingly good condition. It doesn't look like it was in the hands of too many (if any) readers.
Check back next week for another item from the I Am Legend Archive!