"girdle book" were books that was bound in such a way that it had a flexible cover "tail" that could be tucked into one's girdle or belt for ease of carrying. This left the book hanging upside down; when the wearer wanted to read the book, they simply picked it up and opened it. When the book was being read from a table or lectern, the tail would have draped down off the edge. Girdle books started to appear in the late 13thC, gathering popularity through the 14th and 15th, before going well over the top with jewel-encrusted presentation books and falling out of favour late in the 16thC.
The Law of Jutland. Denmark c. 1490.Rostgaard 6 8º. Parchment, 135 fols. The book: 13 x 9.6 cm. The binding is c. 30 cm long. The book has an extended covering of soft leather
There are currently 23 original girdle books in existence, but there are reported to be more than 800 images of girdle books in paintings, sculptures, and graphic arts. The timeframe for girdle books represented in art is from about 1400 to 1600, with a "slight predominance during the 15th century. Most are from the Germanic countries, but France, Spain, Italy, Scandinavia and England are included. The extant girdle books are mostly religious or devotional works on either parchment or paper. Four existing books are legal texts, but those may be special cases, as they are much larger than the rest and were apparently designed to be carried over the shoulder rather than hanging from a belt. modern girdle book