Our Understanding of the physical world was revolutionized in the twentieth century the era of modern physics this book,aimed at the very best students,extends the coverage of the theorical groundwork of today's physics presented in the previous voleme.The present book focuses on the following topics reformulation of quantum mechanics,angular momentum,scattering theory,langrangian field theory,symmetries,feynman ruels and canonical transformation for quantum system.Many problem are included that enchange and extend the coverage.The book assumes a mastery of the material in vol 1.