Where would I find a business directory for the Book Building in 1977?

Hi
I'm a social work student doing research on my cultural history. I live in Boston now, so have been doing a search online only.

I worked for an advertising agency in the Book Building around 1976-78 and can't remember the name. Any suggestions how I could find a business directory, or find the name any other way? I believe it had "Robert or Roberts" in the name.

So sad to see the condition of the building deterioriate. I remember when I felt proud to get a job in a "real" office building, it really was beautiful.

Thanks
Donna

I know the Detroit Public Library has a complete set of Bresser's guides for that period. I believe they index areas much the same way old city directories used to. That would mean there would probably be a few pages listing all Book Building tenants in order.