City System (1988)

From the Back of the Box:

It is called the City of Splendors: Waterdeep, most populous and powerful of the cities of the North. It is a city of wealth, adventure, and danger. More men have died in its taprooms and bars than in all the seiges of Dragonspear Castle. Success and death lurk in its shadowed entranceways and dimly-lit streets.
Come explore the greatest city of the Realms in this incredible new boxes set dealing with urban fantasy adventures. Waterdeep is detailed in no less than 10 expanded maps, embellished with typical building interiors suitable for use in any campaign setting. In addition, a full-size poster of Waterdeep is provided, along with a grand-scale three-dimensional map of Castle Waterdeep, hub of the city's government.

In addition to all these maps, a 32-page City System booklet provides encounters and street scenes, special features and details of Waterdeep, and methods for creating types of buildings in moments and filling the pockets of those unfortunate enough to get in a player character's way. Designed for use with Waterdeep, these new features are suitable for use anywhere in the Forgotten Realms!
It's all here - all you add is your imagination.