FBI demands library records

The FBI has issued the first demand for library records under the Patriot Act. The library in question is somewhere in Bridgeport, CT. The ACLU is seeking an emergency court order to lift the FBI gag order, but they've been instructed by the gag to keep the person whose library records being sought (i.e., their client) a secret. What the ACLU has revealed is that the client is a member of the American Library Association (clearly, a front for terrorism). If any MeFites are interested in digging up additional details on this and start making calls, here's a good place to start. What indeed would the FBI consider so threatening?