I remember seeing this thread a while back and have stumbled
across a good description of the "books", so here it is:
Red-book: Compact Disc Digital Audio (CD-DA). Discs have "Digital Audio" printed below the "CD" logo.
Yellow Book: Compact Disc Read Only Memory (CD-ROM). Discs have "Data Storage" beneath the "CD" logo.
Green Book: Compact Disc Interactive (CD-I) have "Interactive" printed beneath the "CD" logo.
Orange Book: Write-once recordable Compact Discs (CD-R) have "Recordable" beneath the "CD" logo.
Blue Book: CD-EXTRA (formerly known as CD-Plus), discs contain digital audio and data, indicated by a "+" alongside the "CD" logo.
White Book: Compact Disc Digital Video (Video-CD), discs contain MPEG video and have "Digital Video" below the "CD" logo.
I found this at: