What is the most difficult thing you have ever read?

[Leo]

Chelsea wrote: "The book I'm currently reading - The Road to Reality: A Complete Guide to the Laws of the Universe by Roger Penrose - is a 1000+ page monster about mathematics and physics. I attempted..."

Yeah. You need a lot of maths for that one. But be advised the Penrose has some odd, Platonic ideas that puts him at odds with many physicists.

If you want something more mainstream, you may want to try out Standford's Leonard Susskind's "The Theoretical Minimum." I like that he grounds his readers in scientific thinking -- based on observation.

Penrose tends to write from a mathematician's perspective. Where the abstraction is presented devoid of physical explanation. Both are great, I just think Susskind better.