Hobbies are a category of leisure activity that spans a wide variety of practices, including collecting (e.g., stamps, dolls), making or building (e.g., knitting, model rocketry, and woodworking), observing nature, and, perhaps, contributing to science (e.g., amateur astronomy and land surveying), among others. Common to these practices is the fact that hobbies are prototypical of what psychologists call an individual interest—that is, the extended, self-motivated, systematic, and intense engagement in a practice. Investigating how people participate and learn in hobbies, [Page 346]therefore, can shed light on issues central to understanding knowing and learning out-of-school, including the very nature of interest-driven pursuits, the social and cultural organization of hobby practices and how they structure learning opportunities, and the dynamics of interest-driven, long-term learning. This entry begins ...