Well, 'Mutiny on the Bounty' is about the mutiny that took place on the ship. Charles Nordhoff does a great job of bringing the story to life. He describes the different personalities on the ship. For example, the captain's authoritarian style which clashed with the crew. The book also shows the crew's desperation and their reasons for taking such a drastic step as mutiny. It's not just about the mutiny itself but also about the lead - up to it, the events that followed, like where the mutineers went and how they tried to start new lives.
The main themes in 'Mutiny on the Bounty' include leadership. The captain's leadership style and how it affected the crew is a big part of the story. Then there's the theme of freedom. The crew's desire for a different kind of life away from the strict regime on the ship. Also, the theme of adventure, as they are on a long and dangerous sea voyage. There are many events during the journey that show these themes, like when the crew decides to take over the ship in search of a more 'free' life, which is both an act of adventure and a fight for freedom from what they see as bad leadership.
Yes, the story of Mutiny on the Bounty has some basis in real events. But, like many historical accounts, it might have some elements that have been dramatized or exaggerated over time.
To a large extent, it was true. However, like many historical accounts adapted for storytelling, there might have been some artistic liberties taken to make it more engaging. But the core events did happen in reality.