This volume explores the issues with which evaluators of nonformal education programs (such as parks, zoos, community outreach organizations, and museums) struggle. These issues are not unique to nonformal programs and settings. Rather, they pose different sets of problems and solutions from those that face evaluators of traditional education programs. The authors address this topic from extensive experience as evaluators and education professionals who have worked in nonformal education settings. Billions of dollars are spent annually on nonformal, informal, and nontraditional education programs and collaborative formal-nonformal efforts. Public and private dollars fund literally thousands of programs, and yet the field of program evaluation has provided little guidance for evaluating such efforts. There are precious few resources available to lead program administrators, staff, and evaluators through the maze of programs with the diversity of the constituencies that support them. The stakeholders and audiences of nonformal education programs are numerous, and these programs can range from a one-shot, hour-long lecture to an ongoing, one-day-a-week volunteer program, to a three-week study tour, to a four-weekends-across-one-year-work camp, to a "stop by when you can" museum collection.