Book Format definitions

Last week I finished David and Natalie Bauman’s Rare Finds. It does an okay job of explaining some of the more popular categories (Americana, Children’s Lit, Photography, etc.) that people collect (and some nice photography), but the really interesting stuff comes at the back of the book in the indexes, Frequently Asked Questions, Book Bindings and  More Resources sections.

One part that I want to share here is the bit on book formats. If you’re in the market for old books you will see many books’ sizes abbreviated as 4to, 8vo, 12mo and so on. You might also see the terms folio, quarto, octavo, etc. These all indicate how many time a printed sheet was folded in order to produce the pages in the book. So a quarto (meaning one-quarter) means that the original printed sheet was folded once in half and then folded in half again. This gives you 4 leaves (8 pages) all at one quarter of the original sheet.

So folio is folded once yielding 4 pages, quarto yields 8, octavo gives you 16 pages, etc. Now there was no standard size for the sheet of paper that printers started with, so there is some variance in how big to expect a book to be. But here is a handy chart of the average sizes found in older books, from page 73 of the Bauman’s book:

Again, their book is just the tip of the iceberg when it comes to the bibliophile’s world, but it would be good for someone thinking about collecting or for a completist collecting “books about books”.

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