"Not rare, but uncommon"

 "Five second-rate 18th century poets," bound in human skin:

The book, part of the National Library's collection, is one of only two known examples in Australia of anthropodermic binding, a practice that is described in book collecting circles as not rare, but uncommon.

Binding books in human skin dates back to the 16th and 17th centuries, and is usually seen on the odd medical textbook in the libraries of eminent universities, although there are examples throughout history of books bound in the skin of criminals or dead lovers.

The National Library's version, with its macabre handwritten inscription, bellies the rather mundane contents pastoral poems by five second-rate 18th century poets. ... The library has no shortage of exotically bound books - rare books reference librarian Andrew Sergeant has handled volumes bound in stingray, emu, snake and mother-of-pearl, to name a few.

Definitely file under "had no idea this was a Thing." (Link via UffishL on twitter.)