This book is a detailed bibliographic review dedicated to the description of pathologies of primary hemostasis. For each pathology, we include brief background, pathophysiology, diagnosis and treatment with relevant references to give the reader the possibility to search for more details in the literature. We have also created tables to facilitate the presentation of information. This book is intended for students of medicine, pharmacy, dentistry and biology who will find all the essential knowledge concerning disorders of primary hemostasis.It is also intended for all clinicians in various disciplines (clinical hematology, surgery, internal medicine, obstetrics, nephrology, cardiology, rheumatology, gastroenterology) who are faced with the management of patients presenting with a bleeding syndrome due to a disorder of primary hemostasis.