The King's NSA: From 1684 to 1984

Monitoring communication, profiling suspicious persons, doxxing one's opponents long before the arrival of the internet, Europe's kings were already devising sophisticated systems for spying on their subjects. Letters, in particular, were systematically opened and read. A fascinating excursion into the Secret Cipher Chancellery of the Habsburgs, Louis XIV's Black Chamber, and the first era of total surveillance.