This book aims to provide a basic understanding of the principles of in vivo Magnetic Resonance Spectroscopy (MRS),a pioneer technique which is now finding increasing clinical uses in detection of cancer in an non-invasive manner and provide a comprehensive evaluation and assesment of the currect status of MRS in the field of breast tumor detection. It also provides an updated, concise review on breast tumor pathology and MR imaging. It offers some introduction into the in vitro MRS and other future potential diagnostics in the field of breast tumors.