1. Alexander deserves an entire chapter because he has an odyssey all his own.  He made such an impact on the world, and at one point literally ruled half the globe.  Also, he was so wise and also needed part of a chapter devoted to him and Aristotle.  He destroyed several cultures, enslaving and taking the land.  Also, he was so modest about all of his accomplishments; he even gave away almost all of the land he took, and said to his friends that he just had hope left.

2. What made his empire so unique was his idea to expand his kingdom eastward.  He wanted to expand it to undiscovered lands, and to rule every piece of land.  He wanted his army to go on ships and rule any land that they find.