He has been deeply interested in the motivations for a variety of anti-social acts and his continuing novels reflect that interest. Dr. Marks is also interested in Roman and Byzantine culture and published the first book in English on Byzantine Cuisine. He has traveled extensively outside the United States. He is an accomplished cook of both modern and medieval foods. He gardens, raising vegetables for himself and friends. He also turns wooden bowls on his lathe, creating art out of blocks of wood.