As a newly minted librarian, the author volunteered at a grassroots independent library founded to bring together the work of disparate art communities of Chicago. Since then she has participated in many library technology communities with stints on boards, working groups, conference planning committees, and social media-based outreach. Grounded in her research of dozens of community tech projects, she presents a guide exploring how they work, how to get involved, and how to make them better. Library technology managers, grantmakers, scholars, and project managers will all benefit from Heller's incisive discussion of such topics as a historical overview, including the humble beginnings of OCLC and early library computerized cataloging projects, that offers lessons for today; how to find community needs that match your motivation; using personas to learn about community members; choosing a name and legal structure for a new community; five in-depth case studies, including Project Bamboo, Hathi Trust, and the Digital Public Library of America; techniques for project management, documentation, and discussion; forging a path from small, grant-funded projects to a sustained collective good; reconciling hacker ideology and geek culture with inclusive communities; proven methods for supporting tasks and emotions in library tech communities; and successes and challenges of vendor user groups. For readers who want to get started with community technology projects, as well as those who are already engaged in collaborations, the techniques and best practices in this guide will provide the tools and inspiration to make better library technology communities.