the next onebut there were few key places where the topic change was jarringor worseirrelevant the two preceding the discussions about design patterns have been reorganizedreversedand split into three that flow cleanly into the next topic 've also removed an entire on third-party libraries for python this made more sense when both the book and python were new there were only few libraries that had been ported to python and it was reasonable to have best of breed discussion about each of them howeveri was unable to cover any of those topics in detailand franklyi could write an entire book on any one of them finallyi've added an entire new on concurrency struggled with this and can freely admit that it' not directly related to object-oriented programming howevermuch like the on unit testingi think that understanding concurrency is an integral part of all programming and especially of object-oriented programming in the python ecosystem you areof coursefree to skip those if you disagree (or until you discover reason to change your mindenjoy the book and your journey into the world of object-oriented programming dusty phillips