String Theory, Volume 2: Superstring Theory and Beyond Book

I was very pleased with Vol 1 so I'm sorry to say I can't recommend Vol 2. The first few chapters are fairly good where the author excels in the very things they did in Vol 1 (ie detailed worldsheet theory derivation and string perturbations) however, the text really starts to go off the rails quickly. Where this book is really weak is on supergravity and Calabi-Yau but as these are really important topics on which so much else is built, the holes in the treatment are cumulative and by halfway through is reads more like a survey of results than an actual resource for learning how those results come about. The text makes frequent reference to the appendix whenever it requires a result from supergravity but the appendix, though long, is fairly unintelligible and says very little usually just citing really important pieces of the overall structure of string theory making no attempt to justify these things. If these were of secondary relevance to the topics at hand, that would be one thing, but these results are cited again and again to the harm of the book overall. And by Polchinski gets to Calabi-Yau theory, any pretense of actually learning this material is dropped and the author admits that they will just reference results. I ultimately sought other better resources after being disappointed with Vol 2 (I'd recommend Becker, Becker, and Schwarz). Of Vol 2, I can only recommend the first 2-3 chapters.