W HEN we teach material directly from standard textbooks, we and our students often miss out on some of the most interesting aspects of the scientific process. How things came to be the way they are is an intriguing part of science. When I was in school, what is now called the Punnett square was called the checkerboard or chessboard method. Curious about how it came to be called a Punnett square, I did a little digging into old textbooks. I found that the original description of the method by Punnett was clearer than the usual presentation and that in addition, Punnett, following earlier sweet pea breeders, provided some marvelous imagery that facilitates remembering phenotypes. This in turn should help the learning process. The studies of Bateson and Punnett, described here, also provided the first clear example of linked genes. Reginald Crundall Punnett was born in 1875 and, after a classical education, went to work with William Bateson at Cambridge University about 1903. Together with Miss E.L. Saunders, Bateson and Punnett provided much of the earliest evidence for Mendelian inheritance in animals and plants other than edible peas. Punnett became the first Professor of Genetics at Cambridge (1912) and was an expert in poultry genetics. He wrote a number of papers and books on genetics and was a strong supporter of Mendelism, a position which says that all observed traits are caused by heritable characters (genes) that are not acquired as a result of experience but are directly transmitted through germ cells to yield gametes. Punnett clearly saw the implications of Mendelism for all higher organisms as shown by the following quote from his book, Mendelism.