> you mean to tell me... the government has always wanted to know what I read? Call me shocked!

Not really:

> The FBI was particularly interested in learning this type of information about foreign diplomats or their agents.

> ...The area of greatest concern was the information at academic libraries that could be accessed through sophisticated databanks used for research. This point was illuminated by the report that a Soviet employee of the United Nations had been able to recruit a college student from Queens to obtain information at the library that was described as sensitive.

Probably some piece of info you can search for in two seconds on the internet, nowadays.

Libraries used to be where you could obtain detailed maps of your area. Great stuff for planning invasions (which both sides were always doing).