Red Book is the standard for audio CDs (Compact Disc Digital Audio system, or CDDA). It is named after one of a set of colour-bound books that contain the technical specifications for all CD and CD-ROM formats.
The physical parameters and properties of the CD are specified as well as the form of digital audio encoding (16-bit PCM), the optical "stylus" parameters, deviations and error rate, modulation system and error correction, and subcode channels and graphics.
The first edition of the Red Book was released in June 1980 by Philips and Sony; it was adopted by the Digital Audio Disc Committee and ratified as IEC 908.
Recently, some major recording publishers have begun to sell discs that violate the Red Book standard for the purposes of copy prevention. Philips has warned them that including the Compact Disc Digital Audio logo on such non-conforming discs may constitute trademark infringement; either in anticipation or in response, the long-familiar logo is no longer to be seen on many recent CDs.