Handbook of Citizen Science in Ecology and Conservation is the first practical and comprehensive manual for creating, implementing, or improving natural science research and monitoring projects that involve collaboration between scientists and the general public. As citizen science projects become increasingly common, project leaders are seeking information on concrete best practices for planning and implementing projects—practices that allow them to guide and gauge success while also ensuring the collection of high-quality data and rewarding experiences for volunteers. In this handbook, citizen science practitioners from around the world and with decades of experience provide step-by-step instructions, insights, and advice, and they explore real-world applications through case studies from a variety of citizen science projects. This is the definitive reference guide for anyone interested in starting or improving a citizen science project with ecological or conservation applications, from professors and graduate students to agency staff and nongovernmental organizations.