Bruce Leonard Cathie (11 February 1930 – 2 June 2013) was a New Zealand airline pilot who wrote seven books related to flying saucers and a "World energy grid". His central thesis was that he could use mathematics to describe a grid-like pattern on Earth (i.e. the Electro-dynamic field on Earth) that powers flying saucers and controls the dates and places where nuclear bombs can function; in his book "The Harmonic Conquest of Space". His first book Harmonic 33, was published in New Zealand in 1968 and reprinted in the United Kingdom by Sphere Books in 1980. Cathie died in Takapuna in 2013.