This book is the result of a course taught at the École Polytechnique, the aim of which is to introduce students to the challenges facing society in the form of chronic non-transmissible diseases, such as diabetes, Alzheimer's and cancer. We combine the medical approach – asking how are these diseases diagnosed, what is the prognosis for the patient, and which treatments are available with the biological approach – do we understand the origins of these diseases ? If not, why not ? And if so, how can we use this understanding of pathophysiological mechanisms to develop effective treatments ? This is true “Biomedicine”.