This book provides a detailed history of stellar interferometry as practised at Mount Wilson Observatory. It covers the origin of the field in the early 19th Century, and its subsequent development throughout the last hundred years at the Observatory, including the people, instruments, and methods involved in advancing high angular resolution astronomy. Additionally, two extensive Appendices cover the importance of Mount Wilson today as well as an interferometry primer. It is an excellent book for historians, astronomers and anyone interested in Mount Wilson.