In this book the author, Swami Tyagananda, has attempted to bring together Swami Vivekananda’s insights related to the study and practice of karma yoga. The book can be read as a commentary on Swamiji’s teachings on karma yoga. The endnotes in this book point to glowing words [in Swamiji’s karma yoga lectures] in order to encourage the reader to make an independent study of the original books. The structure of this book is simple. The introductory chapter explores the meaning and scope of yoga. It also examines Vivekananda’s classification of yoga into four categories, showing how it cuts across religious boundaries and provides a genuinely universal way to understand spiritual disciplines. The second chapter examines the elements of the karma theory essential to understanding the method of karma yoga. Each of Vivekananda’s four yogas has a “key” with which to unlock its potential. The key to karma yoga is detachment, which is the focus of the third chapter.