Bibliomania is the obsessive purchase or collecting of books to the point where social relations or health are damaged. One of many obsessive-compulsive psychological disorders associated with books, bibliomania is frequently characterized by the collecting of books which have no use to the collector nor any great instrinsic value to a genuine book collector. The purchase of multiple copies of the same book and edition, for example, or the accumulation of books beyond possible capacity of use or enjoyment, are frequent symptoms of bibliomania.

The term "bibliomania" is also used of a more selective but (in some opinions) excessive accumulation of books. These bibliomanes are also obsessed with the hunt, but greater discrimination, resources, and talent lend a patina of respectability to the higher class of bibliomane.

Great collectors of books, like other people who sacrifice their immediate personal interests and society to a particular drive or ambition, may serve the greater good. They assemble libraries of rare or valuable manuscripts and books, but are nonetheless considered bibliomanes in so far as they are driven to collect beyond what are deemed normal bounds.

Other abnormal or condemned behaviour involving books include book-eating (bibliophagy), compulsive book-stealing, book-burying, and book-burning.