Despite the title, the subject is Quantum Electrodynamics, meaning the physics of photons and electrons in interaction. So you'll find Dirac equation, Feynman diagrams, renormalization, Lamb shift, etc. There are hordes of books devoted to that. So what is the difference? The diference is Sakurai. He just couldn't write badly. And here he chose also a very good point of view: avoiding any excess of formalism. The book uses Dirac equations, basic principles of quantum mechanics and relativity, perturbation theory and common sense to derive approximate and accurate descriptions of all phenomena involving photons and electrons, including Lamb shift. You'll learn lots of physics and also Feynman's rules of calculation (the Feynman diagrams). And also a little renormalization. But only a little. Then you could go for the recent tomes of Steven Weinberg on Quantum Field Theory. Farewell!