What are the prerequisites to read his book? Why Richard Phillips Feynman is so famous? What are great works of Richard Phillips Feynman?
It generally happens that some excellent researchers don't teach very well, especially to undergraduates. Sometimes universities prefer that celebrated scientists just focus on research and teach one or two PhD level courses (and bring in lots of money). The reverse is also sometimes true, brilliant and popular teachers don't make a big name in hardcore sciences. Feynman was an exceptional teacher as well as a brilliant physicist. He loved to teach to younger people i.e., undergraduates. As a result, he was not only popular among the physicists (got a Nobel), he was extremely popular among students. Imagine how many young minds he must have influenced in his life. A typical auditorium in the US has 200-400 students. He must have had a big fan base. If you read his Lectures in Physics, you will notice that the style is colloquial and informal-as if he is talking (those books originated from his actual lectures). I bought his books as a reference in my university days, even though physics was not my major.
It is worth noting Feynman's book; QED: The Strange Theory of Light and Matter
This was written specifically to explain the theory of Quantum Electrodynamics for which he shared his Nobel prize to a non-physicist audience. It assumes no initial understanding of physics, just a willingness to follow the discussion.
All along the way he keeps reiterating "No one knows why this is. But it is precisely so." A very satisfying read.