I am a devourer of physics books and myself teacher-researcher. I must say that I have never read an exciting book! you will find the history of the fundamental physics of the 20th century Einstein in string theory whose author is a specialist. What is most admirable is the pedagogy developed here; everything is clear and limpid. Congratulations to the translator (the book is translated from the US): every word is chosen with great precision and fitness, each sentence is tasty. Congratulations!