Dr Jonathan Hughes 
The Rise of Alchemy in Fourteenth-Century England [PDF ebook] 
Plantagenet Kings and the Search for the Philosopher’s Stone

The first book to explore the importance of alchemy and its links to the occult in the period between 1320 and 1400. Alchemists didn”t just try to turn metals into gold: they studied planetary influences on metals and people, refined plants and minerals in the search for medicines. This book illustrates how this branch of thought became more popular as the practical and theoretical knowledge of alchemists spread throughout England.