A crown octavo is a book of 7½-to-9-inch/5-to-6-inch dimensions when closed. The octavo is another standard paperback size, measuring around 5 3/16 × 7 7/8″ (or about 11½ × 17½ cm). Crown octavos contain approximately 48 to 96 pages.
The phrase ‘Crown Octavo’ comes from the Roman word ‘octavus’, meaning eight. This was early book typography before print could produce pages with multiple lines and columns. The Gutenberg Bible (1455 printing) was the first to this size.
In the 18th and 19th centuries, crown octavos were the most common book format. And they were small enough to carry but big enough to hold some decent word count. Literature such as Pride and Prejudice by Jane Austen and Frankenstein by Mary Shelley were first released in paperback form.
While crown octavos are still used today for certain books, they’re much less popular than they ever used to be. Smaller formats gained prominence in the 20th century, with pocketbooks, for example.
Crown 8vos had their share of drawbacks that eventually caused them to decline in popularity. One of these is that the cost to produce them is higher than their smaller counterparts. Another thing is that they’re thicker, meaning they’re less eco-friendly.
While they do not overcome all those flaws, there are positive sides to crown octavos. They’re readable, manageable, and will store a lot of code or text. That’s why they are used for book types like dictionaries and encyclopedias.
This is an essential book size because it is the standard size in most book-formats and publications. This larger size enables more text to fit onto one page, thereby being most economical with space and materials. Furthermore, they’re easy on the hands and easier to stow in your bag or briefcase when compared to other book formats. This makes them easier for readers to carry around (in their e-readers).