Instances of book thefts in Europe and America from earliest times are cited, with particular attention to the activities of the most famous book thief, Count Guglielmo Libri. Measures taken against book thefts are discussed; including work of the American Library Association's Security Committee, 'AB Bookman's Weekly,' and 'Bookline Alert: Missing Books and Manuscripts (Bam-Bam).' Also noted is the Antiquarian Booksellers Association of America's security program as outlined in John Jenkin's 'Rare Books and Manuscript Thefts: A Security System for Librarians, Booksellers, and Collectors.' A concluding decalogue of injunctions is given, designed for the prevention of book thefts and the apprehension of book thieves. A total of 19 notes are supplied. (Author abstract modified)