"John Matthews has spent 30 years studying the traditions of the Celts and is an internationally acknowledged authority on the Arthurian and Grail legends. His many books include "The Encyclopaedia of Celtic Wisdom, The Celtic Shaman," and "The Grail: Quest for Eternal Life," He teaches throughout Europe and America and currently resides in England." 
He has published over ninety books on myth, the Arthurian Legends and Grail studies, including The Grail: Quest for the Eternal (1981), and most recently The Camelot Oracle (2012, with Will Worthington).
Beginning to work with Caitlín Matthews in the 1970s, they wrote and published The Western Way in 1985. This followed the lead of Christine Hartley's The Western Mysteries Tradition (1968) by identifying and promoting a European mystical tradition to offset the then-current domination of Eastern mysticisms from India and China. The Matthews are not associated exclusively with any one pagan or occult group. They studied with two of the leading esotericists of the time, Gareth Knight and Dolorous Ashcroft-Nowicki and between 1988-1992 they served as joint-presidents of the Order of Bards, Ovates and Druids. wiki
"Much in demand as a speaker both in Europe and the USA, he has taught at (among others) the Temenos Academy in London, St Hilda's College, Oxford, and at the New York Open Centre, The Omega Centre, and the University of Seattle in Washington. He has also worked in collaboration with the Joseph Campbell Foundation and Lorian Association, with whom he continues to retain contact. " 
Resources and articles
- The Nile John Matthews, organizational web page, accessed September 20, 2013.