Rainbow Books

So, you know how sometimes after it rains there's a really colorful thing in the sky called a rainbow? Well, there are also books called "rainbow books" but they have nothing to do with rainbows in the sky.

A rainbow book is actually a government document that tells people how to keep things secret. These things might be very important, like how to keep the government's secrets safe.

The reason these books are called "rainbow books" is because they have different colors on the cover. Each color means something different about how secret the information in the book is. For example, green might mean "not very secret" and red might mean "super secret."

The rainbow book also has rules for how people should handle secret information. It tells people who can see it, who can't see it, and what they should do if they accidentally see something they aren't supposed to.

So basically, the rainbow book is a rule book for how to keep secret information safe, and it's called that because it has different colors on the cover.