This book intends to introduce the basic concepts of B cell activation and its latest advances in biological research and disease treatment applications, including the structure and classification of B cell receptors, the process and mechanism of antibody-mediated B cell activation, and tumour immunity and monoclonal antibody therapies. The book is likely to be of interest to university researchers and graduate students in immunology who wish to learn about the core principles, methods and application of B cell activation, and medical practitioners working on tumour immunotherapy.