Apparently there are only so many ways to skin a squirrel. Or, at least, skin it with reasonable efficiency and so the skin is usable. Most of the books I found in the county library system were not terribly new. Hunting is a big enough sport in some areas of the county, but I don't know how many taxidermists are in the area.
The Complete Handbook of Taxidermy by Nadine H. Roberts was originally published in 1979, and seems pretty complete indeed. The other books didn't include how to stuff an armadillo. It even has how to do a mount of a mouflon. There's a touching account about the founders of the National Taxidermy Association in one chapter. The pictures aren't always that clear, as some were taken against dark backgrounds, but the writing is quite descriptive.
Making the Most of Your Deer by Dennis Walrod, published in 2004, says it is a "revised and updated edition of the book More than a Trophy (1983)." There are quite a number of recipes and handicraft ideas. There's part of a chapter in the books with the header "What the Taxidermist Can Do For You," which is pretty informative, and a chapter entitled "Do-It-Yourself Taxidermy." I think for a taxidermist out in the country, mounting deer heads would be a pretty large part of the job.
I skimmed through the Home Book of Taxidermy and Tanning by Gerald J. Grantz, published in 1969, and reprinted up through at least the 1990 edition I got. That one has vivid diagrams.
Practical Taxidermy 2nd Ed. by John W. Moyer, copyright 1953, 1979 (I'm guessing 1979 is the second edition date) has some really good pictures of works in progress and finished mounts.
Taxidermy Guide, Third Edition by Russell Tinsley, copyright 1990, 1977, 1967 has good pictures.
More on those last three later...
Added: I didn't write any more about the last three books, but I read them through. I was surprised that there weren't more recent books in the county library system.