""The Practica: Concerning The Great Philosopher's Stone Of The Ancient Sages"" is a book written by Valentinus, Basilius. This book is a treatise on alchemy and the quest for the philosopher's stone, a legendary substance believed to have the power to transmute base metals into gold and provide eternal life. The author, Valentinus, was a 16th-century alchemist who believed in the spiritual and mystical aspects of alchemy. In this book, he shares...