User experience (UX) is about how interaction with a product, service or system is perceived by its users. Are their needs met or exceeded? Do they enjoy the experience of interaction? Are they going to return? Making user experience the core of software development enhances customer satisfaction, resulting in more sales, higher conversion rates, more returning customers and a stronger brand presence.This book provides a reasoned and authoritative description of what UX is, why it works, what tools and techniques are involved, and how it fits in the software development process, in line with the BCS Foundation Certificate in User Experience, based on ISO 9241-210. How UX fits in the context of other disciplines including business analysis and software testing is also explained.