"There are shadowy periods in our species' past that have been kept hidden from us by more powerful beings."

Dr Howard Lester and his friend Sir Henry Littleway have made a startling discovery: a simple operation on the brain's prefrontal cortex results in vastly expanded consciousness and mental powers, including the remarkable ability to see backwards in time. With their new ability of 'time vision', Lester and Littleway are able to travel back to the days of Shakespeare and even further to the time of the Mayan civilization and the construction of Stonehenge. But their explorations into the distant past and the origins of human existence come with an unexpected and terrifying consequence: something ancient and immensely powerful, long asleep, has been awakened by their activities, and is determined to stop them at all costs.... The Philosopher's Stone is a fascinating blend of science fiction, horror, and philosophy told within the framework of H.P. Lovecraft's mythos.