This toolkit, developed by the Massachusetts Center of Excellence on Problem Gambling Prevention, describes how to use one-on-one interviews (OOOs) as a timely, flexible way to collect information from people who have key knowledge and experience related to problem gambling. It explains how OOOs can help communities explore how different populations are affected, why people gamble, how prevention efforts are working, and how to strengthen partnerships, and provides sample tools and step-by-step guidance for planning, conducting, and summarizing interviews.