This guidebook is designed to help generate successful professional learning communities (PLCs) by providing a set of steps one may wish to consider when developing, recruiting for, and facilitating PLCs. Some aspects may not be relevant to a PLC (each PLC is unique), but this guidebook provides the structure to get started. In following the steps laid out in this guide, one will engage in a systematic approach to building a PLC that is designed to be sustainable and impactful for one's intended community. "Building and Maintaining Successful Professional Learning Communities: A Toolkit for Evolving Emergent, Transdisciplinary Communities of Practice" is designed to facilitate the design and/or the further development of successful PLCs. The guidebook is intended to be a toolkit for all practitioners who wish to systematically explore getting started with and further enhancing their PLC. The toolkit is extensive, and therefore it is anticipated that certain sections may be more useful, based on one's own experiences and engagement with PLCs. The scenarios in the next two sections will provide some direction for which sections will potentially be the most useful for building and sustaining an impactful PLC. [This guidebook is the result of the work of the Network for Emergent Socio-Scientific Thinking (NESST), which is housed at the Smithsonian Science Education Center.]