Preston Jennings (1893-1962) author of A Book of Trout Flies (1935) provided one of the first organized classifications of American angling entomology. In his book he provided a series of fly patterns which imitated the natural insect. At the 1940 New York World's Fair, Jennings exhibited the art of fly-tying and his research on insects and the art of deceiving fish. He studied how the effects of color and light effected the way trout see insects. Above pictured flies are Prism Stone #1, #2, #3. Flies are currently for sale on Art of Angling Website. Photo by Art of Angling.