A book is a number of pieces of paper, usually with words printed on them, which are fastened together and fixed inside a cover of stronger paper or cardboard. Books contain information, stories, or poetry, for example.

A book of something such as stamps, matches, or tickets is a small number of them fastened together between thin cardboard covers.

When you book something such as a hotel room or a ticket, you arrange to have it or use it at a particular time.

A company's or organization's books are its records of money that has been spent and earned or of the names of people who belong to it.

When a referee books a football player who has seriously broken the rules of the game, he or she officially writes down the player's name.

When a police officer books someone, he or she officially records their name and the offence that they may be charged with.

In a very long written work such as the Bible, a book is one of the sections into which it is divided.

If you are in someone's bad books, they are annoyed with you. If you are in their good books, they are pleased with you.

If you bring someone to book, you punish them for an offence or make them explain their behaviour officially.

If you say that someone or something is a closed book, you mean that you do not know anything about them.

If a hotel, restaurant, theatre, or transport service is fully booked, or booked solid, it is booked up.

In my book means 'in my opinion' or 'according to my beliefs'.

If someone in authority throws the book at someone who has committed an offence, they give the offender the greatest punishment that they are allowed to.