**Cathy O’Neil** is a data scientist and author of the blog [mathbabe.org](https://mathbabe.org). She earned a Ph.D. in mathematics from Harvard and taught at Barnard College before moving to the private sector, where she worked for the hedge fund D. E. Shaw. She then worked as a data scientist at various start-ups, building models that predict people’s purchases and clicks. O’Neil started the Lede Program in Data Journalism at Columbia and is the author of *Doing Data Science*. She is currently a columnist for *Bloomberg View*. Photo Attribution: <i>GRuban, CC BY-SA 4.0, via Wikimedia Commons</i>