Multiple myeloma is a plasma cell malignancy characterized by complex heterogenous cytogenetic abnormalities that accounts for 1.4% of all cancers, and approximately 10% of hematologic malignancies. The clinical manifestations of multiple myeloma include lytic bone lesions, cytopenia, hypercalcemia, renal dysfunction, hyperviscosity of the blood, immunodeficiency, and peripheral neuropathy. Based on the clinical and genetic data, probably all cases of multiple myeloma arise from an asymptomatic monoclonal gammopathy of unknown significance. The exact mechanism of the transition from MGUS to overt multiple myeloma is still not well understood. Recent oncogenomic studies have further advanced our understanding of the molecular pathogenesis of multiple myeloma. This book will give a comprehensive overview of the genetic and molecular epidemiology of multiple myeloma in order to get a more refined and conclusive understanding of this disease.