Geoff Crockford started work as a human physiologist with a Medical Research Council unit based at the Dept of Human Anatomy, Oxford. He then moved to the Dept of Occupational Health, London School of Hygiene and Tropical Medicine to run an MSc course in occupational hygiene. Later he became head of the department\'s industrial service unit, and then the department. He learnt to dowse on a British Soci of Dowsers course in 1995, and discovered that there appeared to be no adequate theory as to the physical basis of dowsing or the sensory system involved. As a result he decided to see what was going on. Observations and experiments soon led to the development of the Diamagnetic and Paramagnetic Theory of Biolocation upon which his dowsing work is now based. Geoff\'s dowsing activities include water divining, archaeology (pre Roman), plant, tree and human auras, and dowsing services to industry.