We present a survey of x-ray and electron diffraction studies of Aluminum- Transition Meta1 alloys. The icosahedral phase is found in Al alloyed with Mn, Cr, V, Mo, Ru, W, and Re. The effect of adding small amounts of Si and Ru to the binary alloys is discussed. We review the advantages and disadvantages of various indexing schemes. Distortions of electron diffraction pictures are described in terms of phason strains in a quasilattice