Around 3,800 Germans are newly diagnosed with acute leukemia each year, where cancer cells develop in the white blood cells that normally play a significant role in immune defense. As a result, the immune system becomes non-functional, and other benign blood cells and organs gradually experience dysfunction. The lymphatic form is the most common cancer in children aged two to three years. In contrast, myeloid leukemia typically occurs in individuals over 60 years old. This book provides an overview of leukemia, possible causes, symptoms, and therapies.