The Book of Joshua tells the final realization of the promise of God to lead the Israelites into the Promised Land after their escape from slavery in Egypt. It begins immediately after the death of Moses.
The first section or theme of the book, the vast majority of the book (chapters one through twenty-two) details the conquest of the land of Canaan and its allocation to the tribes of Israel. The control of the territory did not occur all at once; there were many battles over a period of many years, with the extent of land controlled and settled by the Israelites gradually increasing. Once much of the land was under Hebrew control, the division into areas specifically assigned to the different tribes is detailed.
The second major theme of the book, the last two chapters, records Joshua's advice, instructions, and reminders to the people of Israel regarding the commitments and promises God had made to the people, and the commitments and expectations regarding the ways in which the Israelites were to worship and live in return.