This book, The First Crusade: A New History by Thomas Asbridge, gives pretty good, detailed information on Bohemond I of Antioch. We learn a lot about his leadership and how he managed to keep the First Crusade together from Constantinople to Antioch, even helping to capture the city himself. However, the book also follows the First Crusade in general all the way to Jerusalem, allowing us to more fully understand his role within the expedition, but also how it affected him. I hope you enjoy the book as much as I did! :)

I strongly recommend checking out Steven Runciman's History of the Crusades. The first one has Behemond I as a major actor. He is an incredibly entertaining character, and Runciman goes into great detail about him. The book itself is narrative, so it reads very easily. Though, Runciman is a little biased against the Crusaders because he is a Byzantine scholar himself. All three books in the series provide a very good historical overview of the Crusades in general, and paint a great picture of the amazing cast of characters of the time period.

On a side note, one of the funniest things with Bohemond is Anna Komnene's apparent attraction to him from her description in The Alexiad