“This is an excellent book on strings with a discussion of confocal and nonconformal strings. … This book is primarily for advanced students with applications to advanced and intermediate studies.” (Joseph J. Grenier, Amazon.com, September, 2015) “The book emphasizes techniques of two-dimensional conformal field theory as the basis for perturbative string theory. … the book is a welcome (re-)addition ... Read moreto the growing collection of textbooks on string theory, and one that likely will be consulted whenever future generations return to the foundations of the subject. It is totally suited for a course in string theory straddling the undergraduate and graduate level. The occasional mathematician with a physics inclination will also find the book accessible.” (Johannes Walcher, Mathematical Reviews, January, 2014) “This book is amazing! The author presents the string theory in a very pedagogical way. … The book contains a lot of examples and problems and it is a easy reading. … I recommend this book for instructors and students interested in understand the basic principles of string theory. This book will be very useful as a additional reading for more advanced courses in string theory too! Have fun!” (Philosophy, Religion and Science Book Reviews, bookinspections.wordpress.com, December, 2013) “This new textbook features anintroduction to string theory, a fundamental line of research in theoretical physics during recent decades. … It encompasses a range of essential and advanced topics, aiming at mid – to high-level students and researchers who really want to get into the subject and/or would like to look up some facts. … perfect guide for someone with some moderate prior exposure to field and string theory, who likes to get into the principles and technical details of string model construction.” (Wolfgang Lerche, CERN Courier, May, 2013) Show Less