Saul falls upon his own sword in this book (1st Samuel). Stay tuned to see how he dies in 2nd Samuel!
(1 Samuel, Chapter 31) In this final chapter of 1st Samuel, the numerically superior Philistines do battle with their old enemies the Israelites, of whom King Saul is their commander.
According to the book, the battle was very one-sided in the favor of the Philistines. King Saul took numerous arrows and asked his armor bearer to go ahead and kill him, but he would not. So, Saul took a sword and fell upon it, thereby killing him. Pay attention to this detail, because the first chapter of the next book (2nd Samuel), we find a different story of Saul's death.
Anyhow, I still think that the authors of the book chose to end it like this. I'm not sure how historical this story is and how mythical it is. None the less, I would have to say that it was written very weird. The redundancies and the seeming inability of characters to act on what happened in previous chapters, give the impression that 1st Samuel had multiple authors, or multiple manuscripts, which were later just cobbled together.
Who wrote 1st Samuel? Tradition says that Samuel was the one wrote it, but like Moses and the Pentateuch, Samuel's character dies in this book. He dies specifically in Chapter 25. Another theory is that multiple 'prophets', including Samuel, had a hand in its authorship. The other two prophets listed as contributors to 1st Samuel are Gad and Nathan.
More than likely, this book did have numerous authors and also utilized court records and documents from the Israelite nation.