Drawing from extensive laboratory experience and international research, this groundbreaking book is the first to systematically explore digital immunoassays, covering everything from basic concepts to advanced applications. The book is organized into six chapters. It begins with an introduction to immunoassay fundamentals and then provides detailed coverage of digital immunoassay principles. Next, it explores discretization, the key feature of digital immunoassays, before examining the implementation strategies, technical principles, and performance of heterogeneous and homogeneous digital immunoassays. The final chapter addresses practical applications in areas such as tumor marker, neurodegenerative disease, and virus detection. With its comprehensive approach, in-depth content, and broad scope, this book is ideal for researchers in the life sciences, medical professionals, and chemical metrologists. It also serves as an invaluable reference for educators, graduate students, and professionals involved in R&D or management within the in vitro diagnostic industry.