Click on the first two letters of the last name of the person you wish to find.
Firm names are alphabetized using the surnames or first significant word. (For example, "Birge M. Clark & Walter S. Stromquist" is under Cl for Clark; "The Office of D. Wentworth Wright" is under Wr for Wright; "The Design Group" is under De for Design; and RTKL is under Rt.)
Firm names under a particular surname such as Clark are listed after all the persons with the surname Clark.
Most of the entries in the AIA Historical Directory are persons, not firms, because architects join the AIA as individuals.