This handbook provides guidance for individuals looking to build and catalyze networks between organizations and communities. It covers topics such as understanding network roles and structures, mapping networks, connecting people, moving networks to action, and scaling networks. The handbook uses case studies and worksheets to explain network concepts and strategies that network catalysts can use to strengthen inter-organizational collaboration and community impact. The goal is to equip network weavers with tools and processes for transforming networks and spreading successes more broadly.