I approached this book in two parts. First, I went through the first half of the book which is about Physics in various dimensions like Very Special Relativity, Electromagnetism and Gravity., The it passes to the mechanics of the relativistic classical particle, its quantization, the mechanics of classical string and finally their quantization. The author works in the Light-cone gauge formalism and uses the Nambu-Goto action of the string. A good overview of the main facts about the bosonic string is given through out the following chapters, the first half or first part of this book ends on chapter 14 with an introduction to Superstrings. Then I jumped straight to the last two chapters 24 and 25 which are about string interactions and Riemann surfaces and Loop amplitudes in string theory. Here I must point out that he only does the stuff for open strings, I guess because the theory for Riemann surfaces and therefore tree and one loop amplitudes for closed strings is more involved mathematically. But it was nice to see in working action the Schwarz -Christoffel conformal mapping. Then I left this book for a while and only after going through several more books on the subject decided to came back on it for the second part which is called "Developments". Now for this part it is also the best and probably the only accesible introduction to the subject of D-branes, string charges, Non-linear Dirac - Born - Infeld electrodynamics and it even has a chapter which I am about to finish now that makes the contact between string phenomenology and the particle content of the Standard Model (SM) of particle physics which is not easy at all, using the so called or at least he calls them Brane color which when 3 of them together generate U(3)=SU(3)xU(1) gauge fields, the gluons, that couple to one of the open strings end which represent the quarks and 2 left branes together generate the U(2)=SU(2)xU(1) gauge group of the electroweak part of the SM. This is the INTRODUCTION you MUST go through in order to begin to understand D-branes, it also touches on T-duality and the AdS/CFT correspondence, the book is like his author professor Barton Zwiebach at the MIT, simply brilliant!