A guide to Monkeywrenching is a confusing, hypocritical but ultimately entertaining book of mostly illegal advice that offers an interesting ideological look into the often overlooked subculture of eco-terrorism/extremism. It's surprising to see that a book like this could be referred to as underground despite its environmental goals being almost universally accepted. How its fallen out of public view is likely down to the peak of eco-extremism having passed and the subsequent outdating of the book. While most of it still holds true to time, you only have to take a look at its section on computer sabotage to realise it was written in the 1980s (floppy disks are common tech).
Still, large portions of the advice remain relevant and entertaining to read. Still illegal too, as most of the activities suggested are blatantly illegal, either in the form of arson, burglary, destruction of property or improper use of firearms. Due to the nature of these specific portions, it's a deeply interesting look into creative methods of causing damage. Just the knowledge you're learning how to do something you shouldn't gives the reader a thrill, something that stays present through most of the book.
While the excitement may taper off into the more mundane sections even these have interesting tips or snippets of information. And if you want to read it for practical purposes, entertainment is irrelevant anyway. One of the most confusing aspects is a problem for both ways of reading, as often the book will provide detailed instructions on doing something it advises you not to. It could be argued this is purely to void any legal responsibly, but with only certain passages using these warnings while others remain overtly and admittedly illegal I doubt it. One example of this can be found fairly early on, where the reader is advised tampering with or destroying powerlines is detrimental to public relations, dangerous to the monkeywrencher and comes with heavy legal repercussions. Despite this, it's more than happy to provide details on destroying them (even noting which tools fit bolts on pylons to unscrew them), and if you're American even advises which bits to shoot for maximum damage.
Overall and despite these flaws, if you're looking for something to read purely for the pleasure of doing so, A Field Guide to Monkeywrenching offers enough intrigue to at least read through its juiciest chapters while skipping it's more boring passages. In a practical sense, not that I endorse it, but I'd take its advice with a grain of salt and turn to another publication. As far as I know, a fourth or fifth edition doesn't exist, which is probably a good thing.