The Marriage of Heaven and Earth. A sharp and intricate novel set in the 1950s, 'Mercurius' tells the story of a country clergyman's tortuous quest for the Holy Grail of Alchemy, the Philosopher's Stone which transmutes base metals into gold and confers immortality. As he pits himself against the bizarre perils of the Great Work, it becomes clear that his arcane transformations are as much spiritual as chemical. This novel is also a well-researched and annotated exposition of Alchemy.