Blue Book (CD standard) Blue Book (CD standard) The Blue Book is a compact disc standard developed in 1995 by Philips and Sony. It defines the Enhanced Music CD format (E-CD, also known as CD-Extra, CD-Plus and CD+), which combines audio tracks and data tracks on the same disc. The format was created as a way to solve the problem of mixed mode CDs, which were not properly supported by many CD players. The standard is not freely available and must be licensed from Philips. E-CDs are created through the "stamped multisession" technology, which creates two sessions on a disc. The first session of
Philips Records the Philips Recording Center in Baarn, Netherlands, and formed Polyhymnia International (a recording and mastering company) and Pentatone Records (which specializes in SACD releases). Many of the Philips classical recordings have been reissued on the Eloquence label. Universal also released a "Philips 50" series marking the 50th anniversary of Philips Records in the early 2000s; some of those CDs are still in print. Pentatone has released Philips Quadraphonic sound recordings from the early and mid-1970s in 4-channel SACD format, as their RQR Series. Philips' classical catalog was issued on CD under the headings "Digital Classics", "Legendary Classics" and "Silver Line