How to start studying topics Hardness of approximation and PCP's Recently I have done an introductory course on complexity theory ( which covered 90% of sipser text book). Now I would like to study the topics Hardness of approximation and PCP's. Can you please suggest me the best available sources (lecture notes or video lectures) to study these topics from the basics.
I recommend Lectures on Proof Verification and Approximation Algorithms,  E.W.Mayr and H.J.Prömel and A.Steger (Eds.), Lecture Notes in Computer Science, vol. 1367, Springer Verlag 1998. These lectures are very suitable for studying these topics from the basic.