This chapter provided the introduction of NFRs and why NFRs are critical for building software systems. The chapter also explained various KPI for each of the key NFRs that is, scalability, availability, reliability, and so on. The book will cover the most critical 24 NFRs that are applicable for IT applications and systems.

The next chapter describes the taxonomy of NFRs that is, scalability, availability, reliability, and so on. The next chapter outlines the entire lifecycle of NFRs and describes a framework that can be leveraged by business analysts and architects for discovering NFRs on engagements. The framework will focus on the KPI and KRA for each of the NFRs which will be the critical input for the solution design phase.