The FBI’s explosive post 9/11 growth – expanding by thousands of agents and technical personnel – has coincided with a flourishing of below-the-radar FBI units that effectively form the country’s “break glass” national emergency response team. You’ve heard about the FBI’s significantly expanded counter-terrorism role, but they’ve also added dozens (!) of special units dealing with unique problems, like how to secure critical assets, how to track foreign agents inside the U.S., how to clandestinely monitor sensitive technology being developed by academia, and how to defeat an adversary’s ability to track FBI agents and their investigations. Many of these units have no public footprint; you can try to Google them, but you won’t get anything back. Their names don’t show up in FBI budget documents, either – at least, not the unclassified ones.