The clean architecture is the opposite of spaghetti code, where everything is interlaced and there are no single elements that can be easily detached from the rest and replaced without the whole system collapsing. The main point of the clean architecture is to make clear "what is where and why", and this should be your first concern while you design and implement a software system, whatever architecture or development methodology you want to follow.To fully appreciate the book you need to know Python and be familiar with TDD, in particular with unit testing and mocks. Please refer to the series TDD in Python with pytest published on my blog if you need to refresh your knowledge about these topics.