Have a look at http://arxiv.org/abs/1201.0981, where John Schwarz tells about "The Early History of String Theory and Supersymmetry". Read is as if you never had read anything on the topic before. Try.
The results is astonishing. Schwarz tells how string theory arose from a wrong description of the strong interaction and mesons and baryons. He tells how it arose from playing with the mathematics of the strong interactions. Then he tells how he and others generalized it to a framework for the description of all interaction and particles. He never says why this generalization makes sense, which problems it solves, which questions it answers.
The report sound like a man completely lost together with his research colleagues in a world of fantasy Lagrangians, fantasy dimensions, fantasy symmetries and fantasy dualities. There is no attempt to clarify ideas, to clarify the structure of what is being done, to clarify the goals, to present the progress in understanding or to present the advantages of the approach. It is a man running around in a forest of abstract mathematics, telling how pretty it is, but not explaining what he is doing or why. And Schwarz is an old man: he is 70 years old.
When we read texts by the old masters, like Einstein, Schroedinger, Heisenberg, they tell us what they did, why they did it, what dreams drove them, what motivations they had, what discoveries triggered them and why the enjoyed what they did. Schwarz is the opposite. He tells nothing of all this. It is obvious from his account that he is not a master of his field and that he does not know what he is doing. He keeps his motivations for himself. He obviously knows that they are not worth sharing. What a disappointment.