The tremendous progress that has been made in understanding of the biology of breast cancer has resulted in discovery of many new drugs, giving patients hope and prolonged survival benefits. Metastatic breast cancer (MBC) is a dreaded disease and in the past the median overall survival of the patients suffering from this disease was 18 to 24 months. It is still the case for many subsets of MBC patients, but in majority of other types of this disease enormous progress has now been made, making prolonged survivals a reality and something which is expected rather than an exception. The new discoveries include CDK 4/6 inhibitors (palbociclib, ribociclib, abemaciclib), mTOR inhibitors (everolimus), PIK3CA targeting drugs (alpelisib), new HER2-targeting drugs (pertuzumab, T-DM1, neratinib), PARP inhibitors (olaparib, talazoparib), immunotherapy molecules (atezolizumab), new combinations of these and other agents with existing chemotherapy and/or endocrine therapy molecules. Besides these new discoveries, the increased experience with already existing drugs and practices like ovarian suppression/ablation in premenopausal women is also translating in clinical benefit. This book is written mainly for the medical professionals, but it may also serve the general readers to acquaint themselves with the latest developments in medical oncology in the field of MBC management.