While the theoretical concepts discussed previously have been with us for decades now, a few things have recently been changing very rapidly. There is an ever increasing amount of complexity in software products. For example, in object-oriented programming, we might start off with a clean interface between two classes, but during a sprint, under extra time pressure, a developer might cut corners and introduce a coupling between classes. Such a technical debt is rarely paid back on its own; it starts to accumulate until our initial design objective is no longer perceivable at all!
Another thing that's changing is that products are rarely built in isolation now; they make heavy use of services provided by external entities. A ...
