With the proliferation of digital media such as DVDs and MP3s, pirated versions of copyrighted material have escalated. Authors, songwriters, movie-makers, and all types of publishers are clamouring for ways to safeguard their investments and income from this digital thievery. Digital watermarking is a technology for authenticating copyright as well as original authorship and publication. In this work, security experts learn which types of media and applications are best-suited for digital watermarking, as well as how to prevent forgery and theft of digital watermarks. It includes in-depth coverage of advances in this field, especially watermarking audio content.