This book is work of documentary and autobiography with a strong dash of bunkum thrown in. It details, in sometimes exquisite detail, a period of some months in the mid 1960's which the author spent with the Hell's Angles.
Though he was openly writing about them at the time, with work appearing in magazines, he managed to insert himself into the world of his subjects and come away with enough material for a real page-turner. Most of it has a sadly true feeling that highlights the brutality of the criminal bikers and the harshness of their lives. Neither entirely sympathetic or critical, Thompson depicts the bikers as people without a lot of options and for that matter without a lot of the basic skills (and even sense) to find another lifestyle.
In detailing the events and the narrow society in such detail, Thompson mostly leaves it for the reader to draw their own conclusions. And he does so in an unflinching way, diving right into all of the sex, drugs and violence that make up so much of the lifestyle. I get the sense that this book was written before the bikers had aligned themselves with organized crime, so I have little idea as to how well the whole thing applies to today's realities.
As for the writing, it is a bit wobbly. Thompson went on to become quite a famous writer of course, and something of a social phenomenon in of himself. But this early work, however, shows an unevenness in style and a contradictory nature that make it seem more like a series of related articles than a work in the whole.
I recommend it.