Game Angry is an extremely information-packed book. Despite being a fraction of the length of any officially published Dungeon Master's Guide, it provides far more valuable guidance on how to actually run a tabletop role-playing game, while remaining (mostly) system-agnostic. I've now completed the book and reviewed it a second time. This is the best thing on the market for getting into running RPGs.
[5 of 5 Stars!]