This book compiles the latest research on the A1 and A2 forms of cow milk, and attempts to show a correlation between the type of cow milk consumption and reported incidence of certain diseases (type 1 diabetes mellitus, cardiovascular diseases, sudden infant death syndrome and neurological disorders). Cow milk generally contains two types of -casein, A1 or A2. The book describes the A1/A2 hypothesis, its foundation and the genetics behind it. It discusses the two forms of milk and why one is considered more harmful than the other. Seeking to provide a balanced view of the milk types, the books initial chapters highlight the structure, function and physiological activity of -casomorphins. Subsequent sections describe the health concerns associated with A1 milk, and the various case studies and research surrounding it. In turn, the arguments against the hypothesis put forward by EFSA, American Nutritionists and Truswell are also highlighted. The book does not make any recommendations for dairy consumers rather, it is a collection of essential data both in favour and against the hypothesis. Further mechanistic studies involving well-designed animal and human trials at the cellular, molecular, biochemical and immunological levels will be needed in order to draw sound conclusions. Overall, the hypothesis is fascinating, and possibly significant. However, verified and authenticated research with reproducible results is needed to make final consumer recommendations. This timely book offers a valuable resource for researchers and students of dairy science, as well as industry experts.