What to read after The Alchemy of Happiness?

God has sent on earth prophets to teach men the prescription of happiness. This alchemy may be briefly described as turning away from the world to God, and its constituents are the knowledge of self., the knowledge of God, the knowledge of this world as it really is, and the knowledge of the next world as it really is.

"This man, if ever any have deserved the name, was truly a 'divine, ' and he may be justly placed on a level with Origen, so remarkable was he for learning and ingenuity, and gifted with such a rare faculty for the skilful and worthy exposition of doctrine. All that is good, noble, and sublime that his great soul had compassed he bestowed upon Muhammadanism, and he adorned the doctrines of the Koran with so much piety and learning that, in the form given them by him, they seem, in my opinion, worthy the assent of Christians. Whatsoever was most excellent in the philosophy of Aristotle or in the Sufi mysticism he discreetly adapted to the Muhammadan theology; from every school he sought the means of shedding light and honour upon religion; while his sincere piety and lofty conscientiousness imparted to all his writings a sacred majesty. He was the first of Muhammadan divines." -- Dr. August Tholuck