What is Louise Levathes purpose for writing "When China Ruled the Seas: The Treasure Fleet of the Dragon Throne, 1405-1433"

I have not been able to locate any specific information as to Levathes' purpose in writing this book. I did, however, find information that stated Levathes wanted to create a better understanding of Chinese history, and that she also wished to provide a starting point for beginners.... to spark their interest.