For fifteen years, the Texas Master Naturalist program has been hugely successful, training more than 9,600 volunteers who have given almost 2.8 million hours to nature education. This dedicated corps of naturalists provides teaching, outreach, and service in their communities, promoting the appreciation and stewardship of natural resources and natural areas around the state. Hundreds of new volunteers are trained every year, and the Texas Master Naturalist Statewide Curriculum serves as the basis of instruction for trainees who complete a certification course taught under the auspices of more than forty program chapters. The curriculum contains twenty-four units of instruction that range from geology to ornithology to wetland ecology—all written by the state’s top scientists and experts. Available as well to educators, interpreters, and others who may not yet be able to commit to the Texas Master Naturalist program, the curriculum offers an authoritative source of information for anyone seeking to learn more about the natural world in Texas.