This book provides detailed information on the etiology, pathogenesis, diagnosis, prognosis, and treatment strategies for breast cancer. The first section of the book presents epidemiology, risk factors, histopathological, immunohistochemistry, and molecular subtypes of breast cancer based on the receptor status. It also discusses the association of breast cancer with other hormone-sensitive cancers. The second section of the book covers cover BRCA1 and BRCA2-associated breast carcinogenesis, early-stage progression of breast cancer, and noninvasive biomarkers for the early detection of breast cancer. It also discusses the role of epigenetic modifications and non-coding RNAs in breast cancer metastasis and explores these as the biomarkers and therapeutic targets for breast cancer therapy. Further, it discusses the role of fibrinolytic mechanisms and circulating tumor cells in breast cancer diagnosis, prognosis, and treatment. The book also provides an update on oral poly(ADP-ribose) polymerase (PARP) inhibitors to treat breast cancer. Finally, it offers potential new options for personalized therapies for breast cancer patients, including optimizing drug dosage and identifying genetic changes associated with cancer symptom occurrence and severity.