An office scene was shot in the World Trade Center. In 1986, all that was required to gain entrance to every area of the buildings was a phone call, a letter (there was no email), or placing one's name on a list. Company vehicles, including large equipment trucks, were allowed to enter the underground loading areas. Crew members were allowed to enter underground service areas where things like lights, electricity and air conditioning were controlled. The working atmosphere was efficient and professional, but also very friendly and helpful. There was not one person from top to bottom who was not willing to take the time to help solve a problem. Even house electricians hired because of Union rules, men who had no work responsibilities other than to stand and watch, pitched in.
The bookstore Dinah Middleton ran in Montreal was an actual bookstore called "Double Hook" which specialized in books written by Canadian authors. It closed in 2005.