History Of Plymouth Plantation by William Bradford answers a lot of questions for us about the motivations behind, the struggles of, and the journeys of those we know as the Pilgrims. We're all quite familiar with the basics of the Pilgrims and Thanksgiving; however, Bradford is able to fill in the "back story," so to speak, for those early settlers at Plymouth. We know what prompted their need to leave England (their turn to Christ after recognizing their sinful state)--their persecution by nearly an entire country. We learn of their struggles to leave, their eventual journey to Holland, their growing struggles and troubles while there, and their journey to America. Once they land, the journal chronicles their struggles and defeats as well as their victories. Because this is a firsthand, personal account written contemporaneously (meaning at the time of the events), it's a valuable historical document as well as a compelling story. It answers the questions about why this famous group of people did the things they did.
William Bradford's History of Plymouth Plantation can answer any number of questions about the Pilgrims and their journey to Plymouth, if you are willing to ask them! As Lori stated, this history gives the backstory to the famous Thanksgiving narrative all Americans learn as schoolchildren; it shows how much they truly had to be thankful for. In sum,it can answer questions such as "Why did the Pilgrims come to the New World?" and "What was their life like in England and in Holland?"
I am also intrigued by what History of Plymouth Plantation reveals about the religious beliefs of the Pilgrims. It answers the question: "What did the Pilgrims believe about God and his intervention in human history?" It's one thing to read about what they believed; it's quite another to hear William Bradford say that God killed a sailor because he had mocked the Pilgrims and otherwise treated them poorly.
But it pleased God before they came half seas over, to smite this young man with a grievous disease, of which he died in a desperate manner, and so was himself the first that was thrown overboard. Thus his curses light on his own head; and it was an astonishment to all his fellows, for they noted it to be the just hand of God upon him.”
Quotations like this reveal that Bradford and the Pilgrims believed that God intervened in everyday human events and helps explain their fervent and rigid religious practices.