String theory and M theory : a modern introduction String theory is one of the most exciting and challenging areas of modern theoretical physics. This book guides the reader from the basics of string theory to very recent developments at the frontier of string theory research. This book is ideal for graduate students studying modern string theory and it will make an excellent textbook for a 1 year course on string theory. It will also be useful for researchers interested in learning about developments in modern string theory. The book contains about 120 solved exercises as well as about 200 homework problems solutions of which are available for lecturers on a password protected website. BOOK JACKET