The foundation of modern physics... Einstein came up with these theories and changed the way we view our world. Almost everyone knows of Einstein's intelligence, but what many don't know is how well he can teach. These theories are written as a teacher would try to explain to a student...not like one physicist talking to another. Yes, there is an assumption that the reader has a decent understanding of mathematics and physical concepts, but the reader does not need to have an advanced degree in order to understand what he is saying. While many readers may have a difficult time to understand some of the implications of the theories (such as time space dilation), it really is a fascinating read and makes the reader question everything they see around them.