"Who knows what lurks in the stacks of the old abandoned library..." This is a fun movie about a young boy who discovers strange creatures living amongst the old books. For young and old alike...
Bookworm is a popular generalization for any insect which supposedly bores through books.
Actual book-borers are uncommon. Both the larvae of the death watch beetle (Xestobium rufovillosum) and the common furniture beetle (Anobium punctatum) will tunnel through wood and paper if it is nearby the wood.
A major book-feeding insect is the book or paper louse (aka booklouse or paperlouse). A tiny (under 1 mm), soft-bodied wingless Psocoptera (usually Trogium pulsatorium), that actually feeds on microscopic molds and other organic matter found in ill-maintained works (e.g., cool, damp, dark, and undisturbed areas of archives, libraries, and museums), although they will also attack bindings and other book parts. It is not actually a true louse.
Many other insects, like the silverfish (Lepisma saccharina) or cockroach (various Blattodea), will consume these molds and also degraded paper or the starch-based binding pastes – warmth and moisture or high humidity are prerequisites, so damage is more common in the tropics. Modern glues and paper are less attractive to insects.
Two moths, Tineola bisselliella and Hofmannophila pseudospretella, will attack cloth bindings. Leather-bound books attract various other consumers, such as Dermestes lardarius and the larvae of Attagenus unicolor and Stegobium paniceum. The bookworm moth (Heliothis zea or H. virescens) and its larvae are not interested in books. The larvae are pests for cotton or tobacco growers as the cotton bollworm or tobacco budworm.