CRISPR/Cas9 is an anti-viral system found in bacteria, comprising the Cas9 nuclease and a CRISPR-derived targeting RNA, which has recently been developed into a technology for rapid and specific genomic editing in a wide variety of contexts. Cas9-mediated genomic engineering has proven to be generally applicable in model systems, plants, animals, and human cells. These transformative advances are poised to enable disruptive advances in biology and medicine in a very short time frame. It is now possible to introduce mutations to evaluate gene function, generate models of human genetic disease, rewire transcriptional networks, interrogate mechanisms of gene regulation, and correct disease alleles in model systems. In the near term, gene editing has the potential to revolutionize preclinical research, and in the longer term efficient replacement of one sequence with another holds promise as a therapeutic approach for genetic disorders such as sickle cell disease. My group’s current research is focused on better understanding the mechanism of Cas9-mediated editing, the use of Cas9 to discover new therapeutic targets, and increasing the rate at which Cas9 can correct disease mutations in order to cure genetic disorders.