Today, information in medical science increases rapidly and with the communication age, accessing information is quite easy. However, with this increasing knowledge, information complexity has emerged. Thus, despite all this increasing knowledge, the interest and need for basic books has not diminished. Plasma cell dyscrasias are a monoclonal proliferation of plasma cells. They are derived from malignant B lymphocytes. Common plasma cell dyscrasias include multiple myeloma and Waldenström’s macroglobulinemia. During the past decade knowledge of molecular pathogenesis of plasma cell dyscrasias has increased rapidly and there was a remarkable progress in both diagnosis and therapy. With this book, it is planned to collect current information related to “plasma cell dyscrasias” and it covers a wide range of topics including history, pathophysiology, clinical features and therapies of plasma cell dyscrasias. I would like to thank all the authors and İstanbul Tıp Kitabevleri with the hope that our book will be a stepping stone for scientists who are rapidly advancing their science journey.