The Book of Judges sets the stage for Samuel thematically as well as chronologically. The author of Judges (perhaps Samuel himself) stressed the deplorable conditions which existed in Israel before the nation had a King (Judg 18:1; 19:1; 21:25).
The immediate purpose of the Book of Samuel was to narrate the circumstances surrounding the founding of the monarchy in Israel with Saul, the fascinating relationships between Saul and David, and David's rise to the throne. First Samuel narrates the expansion of the kingdom of Israel into an important power. Second Samuel deals with the covenant with David, his sin and the fall from favor, and the disciplines he received for those sins. An appropriate caption for the two books of Samuel would be The Birth and Expansion of the Kingdom. The ultimate purpose of the books was to reveal the divine origin of the messianic house of David, i.e., the family through whom the Messiah would one day come (2 Sam 7:12).
This commentary is written for all reader, not just for the scholarly. Easy to read and understand, the writer has truly made this an enjoyable read.