Geez, I just spent an amazing hour watching Clifford Stoll reminiscing about his hunt for the German hackers working for the KGB end of the 80's.

https://www.youtube.com/watch?v=656058JxTM0&feature=youtu.be

Running our little BBS’s we were blown away in the spring of '89 after the story was released in Germany and 40 years later it’s still fascinating to see the invention of intrusion detection, opsec and other things. If you don’t know Cliff‘s book "The Cuckoo’s Egg", this is a must-read.