Inferno by Larry Niven and Jerry Pournelle
1976 Pocket Books
A paperback first edition, this proof is about 12 inches tall. This was not uncommon, and I don't know why such a form factor was used, but perhaps it is the same reason long galleys were used. In any case, it is an inconvenient size for a shelf. Like many proofs, this one does not have any printing on the spine; another disadvantage to collecting proofs. Another interesting point about this proof is that Jerry Pournelle is given top billing. On the published book, and all subsequent editions (and there were many), Niven gets top billing. I'd like to know the story behind this!