Before he became famous as the “gonzo” journalist who wrote Fear and Loathing in Las Vegas and Fear and Loathing on the Campaign Trail, and before he became the model for the drug-addled, gun-crazy Uncle Duke in Doonesbury, Hunter S. Thompson spent a year hanging out with the Hell’s Angels, the infamous California motorcycle gang. The resulting book was published in 1966.
Much of it is devoted to downplaying the media coverage of the group as bloodthirsty savages who left a trail of destruction everywhere they went. On the other hand, Thompson depicts them as violent losers, not very bright, mostly interested in their motorcycles, being part of the gang and getting high. He got to know some of them fairly well, but that didn’t stop one of them from abruptly punching him one day, after which several more joined in, sending Thompson to the emergency room. That experience probably colored the last paragraph of the book:
It had been a bad trip … fast and wild in some moments, slow and dirty in others, but on balance it looked like a bummer….I tried to compose a fitting epitaph. I wanted something original, but there was no escaping the echo of Mistah Kurtz’ final words from the heart of darkness: “The horror! The horror! … Exterminate all the brutes!”
I read Hell’s Angels after reading an article in The Nation that said Thompson had predicted the rise of Trumpism, i.e. a movement of “left-behind people motivated only by ‘an ethic of total retaliation'”. There are, in fact, a few places in the book where Thompson takes a step back and provides that kind of sociological overview. Thus:
… nobody who has ever spent time with the inbred Anglo-Saxon tribes of Appalachia would need more than a few hours with the Hell’s Angels to work up a very strong sense of déjà vu. There is the same sulking hostility toward “outsiders”, the same extremes of temper and action… 
The attack [on a 1965 anti-war demonstration] was an awful shock to those who had seen the Hell’s Angels as pioneers of the human spirit, but to anyone who knew them it was entirely logical. The Angels’ collective viewpoint has always been fascistic. 
To see the Hell’s Angels as caretakers of the old “individualist” tradition “that made this country great” is only a painless way to get around seeing them for what they really are – not some romantic leftover, but the first wave of a future that nothing in our history has prepared us to cope with. The Angels are prototypes. Their lack of education has not only rendered them completely useless in a highly technical economy, but it has also given them the leisure to cultivate a powerful resentment … and to translate it into a destructive cult which the mass media insists on portraying as a soft of isolated oddity, a temporary phenomenon… 
A toad who believes he got a raw deal before he even knew who was dealing will usually be sympathetic to the mean, vindictive ignorance that colors the Hell’s Angels’ view of humanity. There is not much mental distance between a feeling of having been screwed and the ethic of total retaliation, or at least the kind of random revenge that comes with outraging the public decency….[258-59]
Sociologists call it “alienation” or “anomie”. It is a sens of being cut off, or left out of whatever society one was presumably meant to be a part of…. In the terms of our Great Society the Hell’s Angeles and their ilk are losers – dropouts, failures and malcontents. They are rejects looking for a way to get even with a world in which they are only a problem… The difference between the student radicals and the Hell’s Angels is that the students are rebelling against the past, while the Angels are fighting the future. 
Certainly, many Trump supporters are indeed fighting the future. Although the average Trump voter had a higher income than the average Clinton voter, many of Trump’s supporters are struggling and feeling left behind (as are many of Clinton’s). But just as many of his supporters are trying to hold on to what they have (e.g. nice lives in the suburbs) or what they think they deserve as white, “Christian” Americans (i.e. better lives than everyone else).
So the book was usually interesting, if a bit repetitious, and Thompson could certainly write, but as a guide to modern America, it doesn’t deliver much.