In the west the first books were written by hand on parchment and were incredibly costly to produce. They were locked in special cabinets with multiple locks and all the key holders had to be present when someone wanted to read one.
Later when paper was introduced and printing began, while they were still precious, they were common enough to need bookcase shelving and we got chained libraries. In the United Kingdom these are best seen in many, indeed most, of the ancient cathedrals. The photos here are all from Wells Cathedral in the south west of England. The library was first built in 1485 but these shelves fitted for books and chains were completed in 1685 after the Civil War was over and the Crown re-established. The library contains 4000 books. 
The vast majority of these have paper pages and are covered with leather, usually with pieces of wood to reinforce the covers at the side. The leather is vegetable tanned and has survived five hundred years without problems. Indeed only fire or water, or rough handling taking the books in and out will damage the leather. Bugs of various types can also have an impact although mostly these are attacking the wood or the paper.
In the 19th century rapid vegetable tanning using more astringent tans and introducing strong acids created a huge problem as the leather developed “red rot” and disintegrated into dust. So if you use leather for bookbinding today be careful you are choosing a reputable source that makes safe vegetable tanned leathers. Experts such as J.Hewit of Scotland have been at it for centuries and today use vegetable tans such as Sumac, Tara and Myrobalan.
Vegetable tanned book binding leather like that to be seen in Wells develops a patina of its own over time. This depends, of course, on exposure to light and the type of handling: as well as any spills on it. Indeed, it builds its own personality over time. Its own history.