A more thorough explanation:

A white book is a type of government report that is bound in white. This is common in European and papal affairs. The term "white book" can also refer to the historical document known as the Albus Liber.

• The British government published a white book in 1939 outlining their policy towards Palestine.
• The Vatican released a white book in 2019 detailing their efforts to combat sexual abuse within the Catholic Church.

These examples illustrate how a white book is a government report that is bound in white. They also show that white books are used to communicate important information about government policies and actions.