CRISPR (also known as CRISPR-Cas9) is a powerful biotechnology tool that gives scientists unprecedented access to the genetic makeup of all living organisms, including humans. It originally evolved as an adaptive immune system in bacteria to defend against viruses. When artificially harnessed in the laboratory it allows scientists to accurately and precisely edit genes, almost as if using a word processor. In mice, CRISPR has already been used to treat diabetes, muscular dystrophy, cancer, and blindness. CRISPR has made cultured human cells immune to HIV, and a variety of CRISPR experiments involving human embryos are well under way. But CRISPR is not limited to biomedical applications. It is also revolutionizing the food industry and many areas of biological research. This article provides science educators a broad and up-to-date overview of CRISPR, including its discovery, application, and bioethical challenges. It is imperative that science educators help prepare students, both majors and nonmajors, for this compelling new era of biology.