By definition the book of Numbers lists the number of people in each tribe of Israel. The book of Numbers is the forth of five books written by Moses commonly referred to as the Pentateuch.
The book of Numbers describes the way God instructed Moses to carry out the various ordinations in the Tabernacle also called the Tent of Meetings, ordinances which were only to be carried out by the Levite priests. During the forty years the Israelite tribes were living in the desert or wilderness as it is often referred to, the book of Numbers outlines where they journeyed. A few of the chapters spell out the laws that God gave Moses for them to keep, in order to follow Him faithfully.