Microbiomes are communities of microorganisms - bacteria, archaea, viruses, fungi and other microeukaryotes - that inhabit all of Earth's environments from the human body to oceans and soils. In the environment, human society depends on ecosystem services performed by microbial communities. Microbiomes also influence the functioning of engineered systems such as water distribution and wastewater purification and alter the health environment of our buildings. We are only beginning to discover the complex interrelationships between the microbiomes of humans, animals and plants and host physiology, health, and disease. Hence, microbiome science intersects with a wide range of important issues. Microbiome research has flourished in recent years such that three dozen academic centers/initiatives now exist in the United States. Operating in relative seclusion from each other, these units face similar challenges. This meeting will gather the Directors and Associate Directors of US Microbiome Centers/Initiatives to share best practices and initiate coordination to serve the larger community of microbiome researchers. Sharing of knowledge between the Centers will help move microbiome research forward, initially by helping to address practical challenges and in the longer-term, by helping to address the steep conceptual challenges in field.<br/><br/>The conference will take place at the Beckman Center of the National Academies of Science and Engineering on the University of California, Irvine campus for a day and a half meeting on June 25-26, 2019. The meeting will include ~50 people, with Directors and Associate Directors of 36 identified Centers/Initiatives in the US, including some that are very well established and other others that are just forming and led by more junior researchers. Representatives from federal agencies and private foundations will also be invited to the meeting. The agenda will address: 1. What are different models for the structure and missions of existing centers? 2. What are different strategies for producing the best microbiome science? 3. What are opportunities for coordination among centers? The desired long-term outcome of the meeting is to improve the effectiveness of academic microbiome centers to advance research. The goal of this initial meeting is to determine whether further coordination of a national network of microbiome centers would be useful, identify initial priorities for such a network, and share the results of the conference with the larger microbiome research community.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.