M J T Lewis
Dr Michael Jonathan Taunton Lewis is a historian of the FR and the associated slate industry, and a pioneer Deviationist.
Born in 1938, son of the naval historian Michael A. Lewis, he studied classics at the University of Cambridge which led to his association with the group behind the Deviation project and he was present at the first day of work on site, at the Dduallt spiral, at 3pm on Saturday, 2nd January 1965, winning the lottery to decide to whom fell the honour of turning the first sod. In the following April, the Railway & Canal Historical Society (of which organisation he became a Vice-President) published his significant history of the origins of the FR How Ffestiniog got its Railway, used for reference material in this Wiki. A second edition appeared in 1968 (price 12/6 (62.5p)).
This reflected his early conversion to the academic study of industrial archaeology, teaching it for many years to adult classes at the University of Hull and on courses at the Snowdonia National Park Study Centre, Plas Tan-Y-Bwlch. He authored Early Wooden Railways in 1970; this is still the key text on the subject.
In 1969 he collaborated with Tom Davies, Will Jones, Michael Seymour, Dan Wilson and Norman Gurley in a series of three key articles about gravity slate working on the FR.  Magazine No. 44 also contains an informative letter from Michael Lewis abut the early permanent way materials of the FR. 
Other works of more local interest written by Dr Lewis include Rhosydd Slate Quarry (with J. H. Denton, 1974); Llechi / Slate (Gwynedd Archives Service, 1976); Pioneers of Ffestiniog slate (with M. C. Williams, 1987; Welsh edition as Chwarelwyr cyntaf Ffestiniog); Sails on the Dwyryd (Snowdonia National Park Study Centre, 1989), an important history of the quays, boats and boatmen that serviced the quarries before the railway; and Blaen Y Cwm and Cwt y Bugail slate quarries (2003).