I bought that book a very long time ago--probably '87 or '88. I saw an ad for it in American Artist
and had to order it by mail and wait six weeks to finally get it, as none of the bookstores around me carried it. (No, I don't miss the old days, pre-Internet)
I was in art school then, being taught by Abstract Expressionists, Pop artists, and the stray Photorealist. Postmodernism and Neo-Expressionism were all the rage. And there I was, wanting to know how to paint like (early) Titian or Caravaggio, but nobody there could even begin to teach me (at best, they thought it was rather quaint; at worst--well, I'm not going back there
So after exhausting the library's meager resources, I was excited to see Sheppard's book advertised, and impatient to get it.
I remember feeling a bit let down by it, however. I know I gleaned some useful information from it, but I also recall it being a disappointment. Maybe it was because I'd had the chance to actually see
both a Titian and a Caravaggio by then, and Sheppard's paintings...well, as saintlukesguild says, they looked like Joseph Sheppard paintings.
That said, one book of Sheppard's I did find useful many years later was Bringing Textures to Life;
I learned a lot from that book, and it's one of the few art technique books I still own.