Bacteriophages T2, T4 and T6 were the first members of what has come to be described as the T-even family of viruses, more properly the Myoviridae (Kutter et al., 1995; Repoila et al., 1994). Structurally these viruses have a prolate icosahedral capsid (the head) attached at one vertex to a long protein infection promoting structure (the tail) (Figure 2-1). At the far end of the tail are one or more receptor binding proteins (the tail fibers), also described as adhesins. Bacteriophage T4 has two sets of tail fibers, long tail fibers that are the initial receptor binding proteins and short tail fibers that bind subsequently and trigger the infection process including: an opening of the base of the tail, contraction of the outer sheath of the tail and penetration of the inner tube of the tail through the outer membrane and cell wall providing a path for genome entry into the cell (Kostyuchenko et al., 2005).