What is software architecture? The answer is multi-tiered. At the highest level, there are the architecture patterns that define the overall shape and structure of software applications. Down a level is the architecture that is specifically related to the purpose of the software application. Yet another level down resides the architecture of the modules and their interconnections. This is the domain of design patterns, packages, components, and classes.
I understand that this book is reference material for fundamental concepts in design principles but it is mostly hard both read and understand.
I definitely recommend looking at more contemporary resources, since software development moved forward and even baseline principles the same, they can be expressed in language closer to modernity.