A charismatic teacher and prolific author, his academic specialty was North American architecture, frequently highlighting such unheralded structures as gas stations, restaurants, motels, bungalows and mail-order homes, and exploring their social, cultural and national significance.
A former president of the Society of Architectural Historians, he served as chairman of the art history department at the University of Delaware and as founding chairman of the Department of History in Art at the University of Victoria in Victoria, British Columbia.
From Victoria, he spearheaded an international and cross-cultural approach to the history of art, bringing notable scholars such as Siri Gunasinghe to the new university, and guest lecturers as varied as Immanuel Velikovsky, Boris Piotrovsky and Hans Wolfgang Müller.
In 1988 he settled in Washington DC, archiving an extensive personal collection of architectural photographs.
Gowans acted as a consultant for the Ken Burns/Lynn Novick Film Frank Lloyd Wright (1998).