The author, John Castle has been a metal detector user since 1978. A native of Hampshire, he has lived in Kent with his wife (also a keen detectorist) and family since 1990. He has amassed a great deal of knowledge and experience about metal detecting and related matters and has an extensive collection of books and magazines containing stories about treasure hunting, gold prospecting and piracy from all over the world.

John has written extensively about metal detectors and their use and has had many articles published in nationally-distributed magazines. He regularly field tested metal detectors for "Treasure Hunting" magazine for four years and occasionally still does so for "The Searcher" magazine.

He has appeared on local and national radio several times and has been consulted by legal counsel in several trials involving metal detector users and Treasure Trove Inquests.

He has been a member of at least one metal detecting club since 1978. He has served on their committees and also those of the Southern Federation of Metal Detecting Clubs and the National Council for Metal Detecting.