The New Americans Program at Queens Borough Public Library (QBPL) is well known for the innovative collections and programs it provides to one of the nation's most diverse communities. What is less known is the rigorous analysis of demographic data that provides direction to the program. Wai Sze (Lacey) Chan uses demographics to create as complete a portrait of the library's current and potential customers as possible. Chan became an expert in the geographic information software MapInfo through a continuing education course. Working with a base map of Queens, matched to library services areas, she creates thematic maps dedicated to topics such as the ability to speak English, subway lines, and migration trends, among others. The visually appealing and easy-to-read maps are brought down to the neighborhood level, so the library can know its customers. This article details the work of Wai Sze (Lacey) Chan and how she incorporated her expertise in demographics and geographic information software to help the Queens Borough Public Library know their customers.