I think I have everything he ever wrote, including a small collection of pamphlets he wrote and several audio tapes he recorded. The expensive book The Master Fly Weaver (I got it used before the price went through the roof) is fun to have and more comprehensive (many more illustrations) but the "Art of Weaving Hair Hackle Flies" has most of the weaving nitty gritty.
The best place to see George Grant's work is the highway rest stop and city information/tourism center just North of the Interstate, in the middle of Butte. They have several long banks of nicely-lighted display cases. Theirs is the largest single collection of Grant flies. They have other stuff too. That place is within walking distance of the Butte KOA campground. We stayed at the KOA for three days this summer, for the Butte Folk Festival. Finding the GGrant flies there too was an added bonus.
The audio tapes can be listened to at:
Here are a few more fly photos: