This document provides a comprehensive guide to developing internal communities of practice within an organization. It begins by defining communities and comparing different types, such as communities of practice, work groups, and business units. It then outlines several business challenges that communities can help address, such as knowledge retention and rapid change. The document provides guidance on key elements to establish a successful community, including domain, community, and shared practice. It also discusses potential risks without proper community management and strategies community managers can employ, such as designing for value, catalyzing participation, enabling smart growth, and creating self-sustainability.