The Valenzetti Equation is a fictional book written by Gary Troup, as part of The Lost Experience. The book describes the reclusive mathematician Enzo Valenzetti and his famous theorem, The Valenzetti Equation. Gary Troup briefly discussed the book in part three, four and five of his interview with Laird Granger. The official Valenzetti Equation Book website was launched in July 2006, providing a home for some in-game clues as well as information on Enzo Valenzetti. The site has since been shut down.