In England several people (including children) have been arrested, and prosecuted, (and convicted?) for terrorism offences because they owned things like The Anarchists Cookbook.

http://news.bbc.co.uk/1/hi/uk/7030096.stm

http://www.bbc.co.uk/news/uk-england-manchester-33705944

(The explorer Sir Ranulph Twisleton-Wykeham-Fiennes while on service with the SAS used to work out how to efficiently use explosive, allowing him to keep small amounts after training exercises. He accumulated a small stock of explosive which he used to demolish an ugly damn.

https://en.wikipedia.org/wiki/Ranulph_Fiennes

)