This book fills an important gap in HCI educational resources by emphasizing practical evaluative UX research methods. Inspired by law casebooks, it features case studies from experienced UX researchers that illustrate how these methods shape real-world product decisions and outcomes. Each case study was selected for its adaptability, impact on product development, and focus on meaningful UX measurement, offering authentic learning experiences that engage readers deeply by connecting theory to real-world contexts. The casebook format provides an insightful overview of UX research practice, industry trends, and actionable guidance, integrating familiar concepts with new, practical takeaways. Designed to strengthen UX research as a strategic partner in product development, this resource blends theoretical insights with applied experience, addressing the current challenges in the field and serving as a valuable resource for professionals and academics alike.