Tim Wallace-Murphy (1930-2019) studied medicine at University College, Dublin, and then qualified as a psychologist; he then became an author, lecturer, and historian. He has written more than a dozen books, including The Mark of the Beast (with Trevor Ravenscroft), Rex Deus, and Rosslyn: Guardian of the Secrets of the Holy Grail. This last book provided invaluable source material to Dan Brown for his best-selling novel, The Da Vinci Code. Tim was a dedicated supporter of the restoration and preservation of Rosslyn Chapel, near Edinburgh, Scotland, undertaking excavations and fieldwork with a team of like-minded people, who would become lifelong friends.

Marilyn Hopkins was born in Totnes, England. Gifted with a natural dowsing ability, she has a deep interest in complementary medicine. She spent ten years studying various forms of Christianity and esoteric spirituality. She has contributed to seminars, talks, and lectures including an ecological seminar at Rosslyn organized by the Scottish Ecological Design Association.