Leak provides a survey of Islam, and its relations to Christendom. His work involves the history, distribution, doctrines, and practice of Islam, and argues that the utter unlikeness of Allah is equivalent to agnosticism.

• FOREWORD (page 5)
• PREFACE (page 6)
• CHAPTER I: HISTORY (page 7)
• CHAPTER II: DISTRIBUTION (page 9)
• CHAPTER III: THE BELIEF OF ISLAM (page 11)
• CHAPTER IV: THE PRACTICE OF RELIGION (page 16)
• CHAPTER V: THE IDEALS OF ISLAM (page 19)
• CHAPTER VI: PERSONAL CHARACTERISTICS (page 22)
• CHAPTER VII: THE CONTACT OF CHRIATIANITY WITH ISLAM (page 25)
• CHAPTER VIII: METHODS OF CHRISTIAN APPROACH (page 28)
• EPILOGUE: THE AFTERMATH OF THE WAR (page 39)