We have found many reasons to study the representations of GL(2, q). In Chapter 13, for example, we discussed the molecule buckminsterfullerene or C60 and noted that an understanding of the spectral lines of this molecule requires a knowledge of the representations of A5 ≅ PSL(2, 5). In the last chapter we found that an understanding of the representations of GL(2, q) seems necessary to bound the spherical functions on the finite upper half plane. Also the Ramanujan graphs of Lubotzky, Phillips, and Sarnak [1988] are Cayley graphs for either PGL(2, q) or PSL(2, q), with prime q, using generating sets with p + 1 elements (p denoting a different prime). See also Lubotzky [1994, pp. 96 ff] and Sarnak [1990, pp. 73 ff]. Finally, the representations of SL(2, q) are needed in the paper of Lafferty and Rockmore [1992] where spectra of degree four Cayley graphs of SL(2, q) are studied.