This document provides an overview of quality by design (QbD) principles including ICH guidelines Q8, Q9, and Q10. It discusses key QbD elements such as quality target product profiles, critical quality attributes, risk assessment, design space, design of experiments, and continual improvement. Examples are given of various statistical experimental designs that can be used including factorial, response surface, and mixture designs. The document aims to facilitate understanding of a QbD approach to pharmaceutical development and manufacturing.