This book fills an important gap between pop-sci and proper text books. It introduces QM with all the math without the robotic tone of text books. The book's writing style is conversational and I felt like I was sitting in Susskind's class. The book teaches the minimum necessary math to understand QM concepts which is very nice. I have other mathematical physics books that I have tried to learn QM math from and while those books are more rigorous they are also very boring and I tend to give up after reading few pages of those. This book always keeps it interesting. It took me two weeks of about 2-3 hours of study every day on week days and 5-6 hours on weekends days to finish this book. Unfortunately, I cannot give this book 5 stars because the book does not contain enough exercises. There are few exercises and many of those require proving some minor detail of the concept being explained. That is nice but if there's going to be only a few exercises I would rather have exercises that require me to apply the learned concept rather than proving some detail. This would be an amazing book if it had more easy-medium exercises. In fact last 3 chapters of the book where QM physics is discussed contains virtually no exercises at all. Susskind is  a master at explaining difficult topics and he builds the concepts from ground up where very little is assumed which is very nice. Unfortunately, authors put very little effort in coming up with good exercises for practice. I still liked the book a lot though as now i feel prepared to tackle a proper text book such as Griffiths.