The Prince by Niccolo Machiavelli is advanced reading for a high school student, but it will repay your effort in the way in which it will help you understand the Renaissance in particular and politics in general. The key to understanding the first few chapters is grasping the situation or context of the work.
Niccolò di Bernardo dei Machiavelli (1469 – 1527) lived at a time when the area that now constitutes modern Italy consisted of a group of small warring city states, each functioning as an independent nation. He lived in the Republic of Florence, a city-state in Tuscany nominally ruled by a governor and city council, but often practically controlled by the wealthy and powerful Medici family, particularly the Duke Lorenzo "the Magnificent" (1469–1492), replaced by a brief democracy from 1498 to 1512. The most constant element of Italian politics in this period was uncertainty, with the papacy and French and Italian kings vying for control over the fractured political landscape of Italy. Machiavelli himself was from a family of the minor nobility, and rose to important positions as a diplomat and military officer during the democracy.
In Machiavelli's period, there were many books written as guides to politics based on the assumption that states or nations were normally run by hereditary rulers. These books were often called "Mirrors for Princes" that created verbal role models for hereditary rulers. Machiavelli's work is innovative in that it describes how a leader ("prince") who is not a hereditary monarch should behave in order to gain and hold power. It is also distinctive for its relentlessly pragmatic viewpoint.
In the first few chapters, Machiavelli focuses on the different types of states and their leadership. He divides leaders into hereditary monarchs who inherit stable kingdoms and those who come to power by other means, conquest or political maneuvering. Next, he thinks about the basic political structures of states (a term encompassing both city-states such as Florence and nations -- not "states" in the modern sense used to describe the regions of the United States) in his time. He notes that leaders exercise power in one of two manners. First, there are kingdoms with many powerful nobles (such as medieval and Renaissance England) in which the leader relies on the nobility for regional leadership and governance and primarily exercises his leadership by cajoling or dominating the nobles. Other states have a weaker nobility and are governed by the leader with the aid of a bureaucracy.