This is a sermon series that teaches the Book of Joshua. It was probably written after the death of Joshua (24:29, 31) and it covers a generation, the twenty-five years between Moses and the Judges, from the death of Moses to the death of Joshua.
Many people are surprised to learn that Joshua was not considered to be a historical book by the Jewish People. In the Hebrew Bible it is included in the section of the Former Prophets. To be sure, it is historical, but it is history written from a prophetic perspective. The writer was not so much concerned about every historical detail, but rather with the way the facts point to God's purposes for Israel and for the world. So, the author selected and presented the facts that would glorify God and allow people to learn from God's dealings with Israel, even as Israel interacted with others.
The book centers on God's faithfulness to His people, particularly as He made good on His promise of a land for them. God had promised the land to the patriarchs and to Moses. Joshua tells us how that promise was finally fulfilled.