The use of photoemission to determine the electronic structure of solids is discussed. The three-step model of photoemission is outlined. Results from crystalline and amorphous Ge are used to illustrate a successful use of photoemission to determine electronic structure. Data from Si is used to illustrate the use of photoemission to investigate surface states and surface reactions. Finally, results from Ni and other materials are discussed to illustrate the minority of cases where difficulty remains in interpreting photoemission in terms of existing models