David was indeed one of a kind & all who play the Dulcimer, especially in Ireland, owe him so much, for all the work he did, especially on researching the players, but also in helping to raise the profile of this instrument, here.
Yes, all dulcimer players and lovers of the instrument acknowledge David's enormous contribution to our understanding of its history and development in his 2 volume PhD thesis (The Dulcimer. 1976), as well as his detailed descriptions and interviews with a particular generation of players, in his book and recording 'All the Tunes that Ever There Were'. I hope his website at www.new-renaissance.net/ will remain open. A lot of his thesis is available to read online - just click on 'Music' on the contents list at the left hand side of the home page.