Over a thousand years ago, the Persian physician and chemist Abu Bakr Muhammad ibn Zakariya al-Razi presented his students with a book of alchemy instructions called the Kitab al-Asrar or Book of Secrets. For over seven hundred years this systematic text on managing chemicals, equipment, and procedures was copied and imitated throughout Europe. Using historian Julius Ruska’s authoritative German translation, this book presents al-Razi’s Book of Secrets in English for the first time and analyzes it from the perspective of a modern scientific laboratory.The Kitab al-Asrar offers a view into the understanding of chemistry and procedure organization in the tenth-century Islamic world. Yet a careful reading yields even more than that. As a laboratory manual, it gives intriguing clues into Persian culture under the Abbasid caliphate: the relationship of teacher and student; attitudes toward safety, labor, and quantification; tools and logical problem-solving; commerce and the availability of luxury goods; and the value of the written word. This is the Kitab al-Asrar.