What is the meaning of "White Paper"

an important book or paragraph published by government offically with a white cover called white paper or white book, this also has some difference. white paper usually has very short paragraph and white book usually is a book with a lot of information inclued, but it also is used in some country for same meaning. Also some countries don't use the white as their cover by habit, they are like to use blue, yellow or green as their files cover color, and this type of files also have a name with blue paper, yellow paper or green paper. and the more information, you can refer to wikipedia with following link address: http://en.wikipedia.org/wiki/white_paper