This book covers the science of measuring the invisible building blocks of thought processes that are useful for understanding humans, including technology users, media consumers, and consumers of goods and services. It provides: An explanation of what self-report measurement entails for beginners; A clear set of assumptions needed in order for self-report measures to yield valuable information; A mindset that needs to be adopted when using self-report measurement in the contexts of surveys and experiments; Guidance for extracting opinion from social media text content and integrating AI; A roadmap for quantifying the errors associated with self-report measurement.