This book coming from the pen of the first serious Japanese scholar on Islam, discovers the substantiative structure of Quranic teaching in a fourfold relationship between God and man, viz 1) God is the creator of man; 2) he communivates His Will to man through Revelation; 3) there subsists a Lord-servant relationship between God and man and 4) the concept of God as the God of goodness and mercy (for those who are thankful to Him) and the God of Wrath (for those who reject Him). Dr Izutsu's description of the historical evolution of these concepts in pre-Islamic Arabia upto the appearance of Islam is quite rich and valuable.