This document summarizes hormonal treatment for breast cancer, including the history and mechanisms of various endocrine therapies. It discusses the timeline of developments in hormonal therapies from the late 19th century to present, covering areas like surgical oophorectomy, tamoxifen, aromatase inhibitors, and more. Key findings and mechanisms of different therapies like tamoxifen, aromatase inhibitors, and fulvestrant are summarized. The optimal use and duration of adjuvant tamoxifen therapy is discussed based on various clinical trials. The relationship between tamoxifen benefit and estrogen/progesterone receptor status is also covered.