This is the complete set of books one through four."Liber de Secretis Naturae," by Ramon Llull, delves deep into the intertwined realms of alchemy, medicine, surgery, proto-chemistry, and early medieval science. This enigmatic work, believed to be a pseudo-Lullian creation originating from a clandestine medical school, uncovers the hidden secrets within these disciplines. With profound insights and teachings, the book unveils the intricate connections between nature's mysteries and the transformative powers of alchemical processes. It sheds light on ancient medical practices, surgical techniques, and the emergence of early scientific thought. "Liber de Secretis Naturae" stands as a testament to the pursuit of knowledge and the quest for the quintessence of life's elixirs, offering a glimpse into the mystical and practical aspects of healing arts and medieval scientific exploration.