A brief review of the electronic and vibrational structure of amorphous As is presented. Using the random network model as a proto‐type for the structure of the amorphous phase, theoretical electron and phonon densities of states are calculated. The influences of topology on these state densities are examined by using ’’cluster‐Bethe‐lattice’’ techniques. These results are then used to interpret the experimental X‐ray photomeission and infra‐red absorption measurements on amorphous As. It is shown that As is one of a small class of unique materials which exhibit an isomorphism between their electronic and vibrational excitations.