What is the fine-grained topic of the following text: Students of Middle Eastern history and geopolitics would do well to pick up a copy of Xerxes Speaks, which delves into the first 200 years of the Persian Empire and it’s rapid expansion into a world superpower. Only return the topic.
The Persian Empire's first 200 years and its rapid expansion into a world superpower as depicted in the book "Xerxes Speaks".