Red Book refers to the technical criteria required for CDs - in other words, its a technical standard that all manufactured CDs must adhere to. When you get a CD manufactured, you might hear that you need to send a master that meets Red Book standards, which means it meets these general criteria. Red Book standards include:
- Maximium duration of 74 minutes
- Each track must be at least 4 seconds long
- Maximum of 99 tracks
- Maximum of 99 index points
- IRSC code
In recent years, many companies have begun manufacturing CDs that do not meet Red Book standards, usually so some kind of anti-piracy software can be added to the disc. This is why sometimes you end up with a CD that won't play in all of your CD players. Likewise with CD-Rs, that can hold more than 74 minutes of recording but may have some playback issues.