Take a look at "The Road to Reality." It starts assuming nothing more than basic arithmetic, and builds up to differntial equations, tensors, string theory, qu

Take a look at "The Road to Reality." It starts assuming nothing more than basic arithmetic, and builds up to differntial equations, tensors, string theory, quantum relativity, etc. I'm warning you up front that it's very math heavy. It takes some work to get through, but its worth it.