In the future world in which Slippery Jim diGriz exists, crime is practically non-existent thanks to a combination of genetic screening and social control. The few malcontents who do exist are therefore aberrations, the most talented of which make life extremely interesting for law enforcement officers, who spend most of their time dealing with petty crimes like burglary and shoplifting. DiGriz himself explains the situation -- and himself -- in this way:
That is almost the full extent of crime in our organized, dandified society. Ninety-nine per cent of it, let's say. It is that last and vital one per cent that keeps the police departments in business. That one per cent is me, and a few others like me, a handful of men scattered around the galaxy. Theoretically we can't exist, and if we do exist we can't operate - but we do. We are the rats in the wainscoting of society - we operate outside of their barriers and outside of their rules. Society had more rats when the rules were looser, just as the old wooden buildings had more rats than the concrete buildings that came later. But they still had rats. Now that society is all ferroconcrete and stainless steel there are fewer gaps between the joints, and it takes a smart rat to find them. A stainless steel rat is right at home in this environment.
It is a proud and lonely thing to be a stainless steel rat - and it is the greatest experience in the galaxy if you can get away with it. The sociological experts can't seem to agree why we exist, some even doubt that we do. The most widely accepted theory says that we are victims of delayed psychological disturbance that shows no evidence in child-hood when it can be detected and corrected and only appears later in life. I have naturally given a lot of thought to the topic and I don't hold with that idea at all.
A few years back I wrote a small book on the subject - under a nom de plume of course - that was rather well received. My theory is that the aberration is a philosophical one, not a psychological one. At a certain stage the realisation striked through that one must either live outside of society's bonds or die of absolute boredom. There is no future or freedom in the circumscribed life and the only other life is complete rejection of the rules. There is no longer room for the soldier of fortune or the gentleman adventurer who can live both within and outside of society. Today it is all or nothing. To save my own sanity I chose the nothing.The Rat is thus a professional criminal in a world where such people are practically non-existent -- but not completely so. As he soon finds out, there are other people like him and the role they play in society is quite different than the one he chose for himself. I won't spoil the story by saying any more, except that Harrison creates a terrific vehicle by which the Rat can continue to have exciting adventures that are more than just endless con games and bank robberies. He also provides himself with plenty of opportunities for satire, social criticism, and philosophy in the best traditions of classic science fiction. I quite often disagree with the points of view Harrison advances in the Stainless Steel Rat stories, but I can't deny that he spins a good tale. Likewise, Jim diGriz makes for a great protagonist, as charming and self-rationalizing as any a lovable rogue in pulp literature. Plus, he's a native speaker of Esperanto, so what's not to love?