Revolution Man is the twenty-first book in the stupidly long series known as the Eighth Doctor Adventures (no, not those ones, for god's sake) and it involves a man who wants to do some revolutionising. Also, lots of drugs, because it's set in 1967 and apparently back then everyone was just off their fucking tits all the time. It's a shame Rose isn't around, she would've loved it. It's written by Paul Leonard, who isn't even interesting enough to have his own wiki page. Sucks to be him. But he wrote a controversial as fuck book, so you'd think he might qualify.
What is important, however, is that the Doctor whips out a revolver and straight-up just blows some dude's brains out. I'd say "spoilers," but, you know, we really should've seen this coming. I'm sure he had a good reason for it though... r-right?