Just before we took off for a 10 day vacation, I read, edited and returned the final set of pdfs (page proofs) for my forthcoming novel A Stone for Bread. This was the second reading and like the first was a process that can be both exciting and tedious — exciting to see the novel actually in print, tedious in having to take great care ferreting out those pesky typos and often overlooked misspellings, particularly in a novel with numerous French words.
But what most intrigued me about the process itself was its nomenclature. It’s understandable that in this computer age, publishers use the term “pdf” to describe type-set pages, because proofreaders receive them as pdf computer files. But what about the formerly more common terms, galleys and page proofs? And what’s the difference between them?
According to most definitions, the term “galley” or “galley proof” comes from a first print run of a manuscript before it’s separated into pages. This originated in the early printing press days. An example of this below is the first galley proof from Proust’s Remembrance of Things Past: Swan’s Way, with the author’s corrections. 
Page proofs would then be the next step in the process, with the corrected and separated pages given a final proofing.
These days both steps in the process can be done in pdfs.
But what’s a “Cape Cod?” I first heard this term years ago when I was an editorial assistant in the Fiction Department of Good Housekeeping Magazine. The magazine not only published short stories then, they sometimes condensed a novel. These novels came to us in a proof called a Cape Cod, bound in a cheap paper cover. I was told the name came from the company on Cape Cod that provided these to publishers for marketing purposes.
Happily, today’s internet allows us to flesh out the story. Here’s what I found: in the 1950s and 60s, before I worked at Good Housekeeping, a company called Crane Duplicating Service, located on Cape Cod, sold publishers on the idea of cheaply bound page proofs printed before a book’s publication, which could then be sent in advance to reviewers. What was most interesting to me was that these editions became known to publishers not as the “Cape Cods” we called them at Good Housekeeping, but as “Cranes.” Probably the company encouraged that name as its own marketing strategy.
But if you’re a publishing geek, the information about Crane Duplicating Service and more history on galleys and page proofs came from Ken Lopez Books, and yes there are collectors out there for old galleys and page proofs.