I took the dust jacket off the book so that the wrinkles in the plastic would be more apparent.
As a conservator my eyes have become attuned to very fine details. I notice things even when not actively engaged in documentation of an object. When this book, an edition of Catcher in the Rye published in the UK in 1951, was handed to me at the circulation desk I immediately noticed that the plastic wrapper on the dust jacket was wrinkled and distorted and that it the dust jacket had been damaged. Note on the "back" of the dust jacket that the paper has a horizontal compression fold that obscures the last title in the "list of fiction".
Here's an inside view showing the vertical wrinkles in the plastic wrapper and tears in the paper dust jacket. The wrinkles are a result of the degradation of the plastic which shrinks and warps as it ages. It is surprising how much damage a plastic wrapper can inflict, but clearly the plastic is stronger than the paper given the fractures and creases in the dust jacket.
Not all plastics are bad, we use archival polyester in a number of preservation applications, but if you see any that is wrinkled and distorted, be sure you're not using it to store or protect an artifact as you may wind up inflicting damage that you had hoped to prevent. The wrapper is now off the dust jacket which will get an upgraded wrapper made of archival polyester and then the book can go back to the shelf.