A few months ago, someone noted in the comments that they hadn't heard about the Therac-25 incident. I was surprised, and went off to do an informal survey of developers I know, only to discover that only about half of them knew what it was without searching for it. I think it's important that everyone in our industry know about this incident, and upon digging into the details I was stunned by how much of a WTF there was. Today's article is not fun, or funny. It describes incidents of death and maiming caused by faulty software engineering processes. If that's not what you want today, grab a random article from our archive, instead. When you're strapping a patient to an electron gun capable of delivering a 25MeV particle beam, following procedure is vitally important. The technician operating the Therac-25 radiotherapy machine at the East Texas Cancer Center (ETCC) had been running this machine, and those like it, long enough that she had the routine down.