In his “Alchemy of Happiness” there is a beautiful chapter on “Know Thyself.” The parable there used regarding man’s soul and the enemies that lay siege against it reminds one very much of Bunyan’s “Holy War.” The shortest of his works, as far as I am aware, is called _Al-Qawaʿid Al-ʾAshara_ (The Ten Articles); this has been frequently reprinted. It consists of ten principles of faith and conduct, and is scarcely longer than an ordinary letter. Of a similar character is _Risalat-ut-Tair_ the parable of the birds. His most celebrated treatise on ethics and conduct is entitled _Mizan ul ʿAmal_. It might be compared to the book of Ecclesiastes or the first chapters of the book of Proverbs. In the introduction Al-Ghazali shows the folly of those who neglect to secure the happiness of their immortal souls as well as the peril of those who despise faith in the world to come. The true way of happiness consists in knowing the right and doing it. The soul is a unit and its various powers are knit together and are interdependent. The path of the mystic unites true faith with true practice. He also speaks of the possibility of change of character through religious devotion and mentions the virtues that are to be cultivated and the vices to be shunned on this pathway to God and to true happiness. To emphasize the importance of life with its brevity and the supreme importance of eternity Al-Ghazali says: “Suppose we imagine that the whole world is filled with dust and that a little bird should come and snatch up one atom of dust every thousand years. We know that there would be an end of its task, but nothing would have been taken away from the everlasting character of that eternity which has no end.” Although the moral teaching of this book is very noble, it is after all based entirely on the principle of salvation by works. There is no hint of the possibility of the transformation of character through regeneration of the heart, nor is the way pointed to the victorious life by overcoming temptation through a power that is not our own. Of all his writings none is celebrated more justly than his greatest work “The Revival of Religious Sciences” (_Ihya ʿulum id Din_). It is a veritable encyclopædia of Moslem teaching and ethics and covers the whole range of Moslem thought. Many editions of this work have been printed and commentaries written on it, the most celebrated of which is by Mohammed-uz-Zubeidi Al-Murtadha, in ten large volumes. The work itself consists of four volumes of ten books each and has a total of over one thousand closely printed pages. Although widely read in its original form, popular demand has called forth several abbreviated compendia of the work. One of them entitled “A Homily for Believers,” by Mohammed Jamal-ud-Din of Damascus, is used as a text-book on Islam in the Theological Seminary of the American Mission in Cairo.