Quality Attributes: Architecting for the -ilities
Why the non-functional requirements — performance, scalability, availability, security, maintainability and their kin — are what your architecture is actually optimized for, how to make them measurable, and why they always trade off against one another.
The non-functional requirements that actually drive architecture: the -ilities (performance, scalability, availability, security, maintainability…), making them measurable as scenarios with numbers, and prioritizing the top few because they all trade off.