The ELF documentary
"If a Tree Falls: A Story of the Earth Liberation Front" is a new documentary just out. It goes deeper and with way more access than anything before. It aired on PBS Tuesday and it's viewable for free on their website for the next few weeks.
Somehow I had thought the ELF in the US went way back further; in fact it started in the later 90s. The documentary focused on one particular cell, so it was hard to get a sense of the whole scope. But do watch it.