The guy's actual name is Galen Govier.
His business was (is?) called Galen's Tag Service.
(Or GTS for short)
I do not know the man, and other than buying the ''White Books'' from him years ago, I have had no dealings with him.
It is rumored that he is slow in working these days, and only deals with the most rare and expensive Mopars specifically, but I can't say either way if this is true.
At any rate, with the research that he has done over the years, my opinion is that he has done a great service to the Mopar community in general.