I learned about Leonard Susskind's book(s) in Philip Ball's excellent Beyond Weird. A quote from Ball: "Suskind has organized the material so as to tell you what you need to know in the order that you need to know it, in distinction from the common practice of introducing topics and concepts in more or less chronological order." The book series is based on the free online video course also called The Theoretical Minimum.
Personally, I think his approach is wonderfull, introducing the general reader to the actual equations in a very clear way that is not intimidating, countering the impulse of people to simply philosophize and let their imagination run riot.