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This book is pretty poorly written from an organizational standpoint. There is no flow of thought, or building up of knowledge from fundamental to secondary to more advanced. I don't doubt everything in the book is true, but the way it is presented in a non-contextual manner makes it a pretty poor read and medium for learning. The prices is absurd given these facts.
This book contains very useful information about stock options. Unfortunately, the section gamma scalping needs to be re-written. It contains gross errors based on inaccurate explanations of position greeks in Chapter 13. For instance, during an example, the author asserts that a position delta of +5.60 is equivalent to being long 560 shares of stock. This is false. The position delta represents the sum of the deltas of underlying instruments. Having a long position delta of of 5.60 means you are equivalent to 5.60 shares of long stock. The problem arises from the fact that he is discussing the "equivalent contract position" instead of the "equivalent stock position" without alerting the reader to the change in the basis of measure.
Consequently, while I enjoyed reading most of the book I feel this book should be rated low due to the magnitude of the errors and the difficulty a novice reader may have in following his examples in certain sections.