Many science teachers recognize that teaching aspects of the history of science helps students learn science content and the nature of science (NOS). The use of history can potentially humanize science, help students refine their critical thinking skills, promote a deeper understanding of scientific concepts, and address common student misconceptions that often resemble those of past scientists (Matthews 1994). However, the challenge for teachers is how to effectively incorporate history into the science classroom, while at the same time being mindful of the multiple constraints that govern classroom practice. This article describes the various steps to an approach to the use of history of science that may provide some insights for instructors of K-12 classes and includes two examples--one from a classic story of evolution, and another from the history of sickle-cell anemia research. (Contains 5 figures.)