The controversial National Security Letter (NSL) statute could be significantly expanded under two separate bills currently being debated by the Senate. Every year, the FBI issues thousands of NSLs to telephone and Internet companies, demanding records about their customers and gagging the companies from informing the public about these requests. NSLs are inherently dangerous to civil liberties because their use is rarely subject to judicial review. But NSLs are not magic, and they don’t require recipients to do whatever the FBI says. Above all, the type of information available to the FBI with an NSL is quite limited, reflecting the need to tightly control the extrajudicial nature of this controversial power.