James Bolivar diGriz, alias "Slippery Jim" and "The Stainless Steel Rat", is a fictional character and a series of comic science fiction novels written by Harry Harrison.

James Bolivar diGriz goes by many aliases, including "Slippery Jim" and "The Stainless Steel Rat". He is a futuristic con man, thief, and all-round rascal. He is charming and quick-witted. He is also a master of disguise and martial arts, an accomplished bank robber, a criminal mastermind, an expert on breaking and entering, and (perhaps most usefully) a skilled liar. Master of self-rationalization, the Rat frequently justifies his crimes by arguing that he is providing society with entertainment; and besides which, he only steals from institutions that he believes have insurance coverage and so will be able to recoup their losses. He displays a strong sense of morality, albeit in a much more restricted sense than is traditional. For example, diGriz will steal without compunction, but deplores killing.

The character was introduced in Harrison's short story "The Stainless Steel Rat", first published in 1957 in Astounding magazine. The story introduces the Rat, who has just carried out a successful larceny operation, and subsequently details a complex bank robbery the Rat pulls off with ease; however, he is outfoxed by the mysterious "Special Corps"—a crime-fighting organization staffed with former criminals—and recruited by them in order to fight crime. Harrison used the story, with minor modifications, as the introduction to the series's first full-length novel, also called The Stainless Steel Rat. Like other characters created by Harrison, the Rat is a speaker of Esperanto and advocates atheism.

There are 12 works in the Stainless Steel Rat series.

The series takes place in the far future, to the point where the name and location of the original homeworld of humankind has been lost. According to professor Coypu, the Gregorian calendar is no longer in use (with no mention of what replaced it), but The Stainless Steel Rat Saves the World provides a timeframe for the Rat's life and adventures when DiGriz is sent 32,598 years into the past and arrives in 1975 A.D., which would place the events of the series around the late 346th century.

The Stainless Steel Rat, The Stainless Steel Rat Saves the World and The Stainless Steel Rat for President were adapted into comic strip form in early issues of 2000 AD, written by Kelvin Gosnell and drawn by Carlos Ezquerra. Ezquerra drew Jim with an appearance modelled on the actor James Coburn. They appeared in the following issues of 2000 AD:

The first appearance of The Stainless Steel Rat in prog 140 was supposed to be preceded with a brief panel of explanation of who Jim was. However, an editorial error meant that the panel actually appeared at the end of the first episode, not the beginning. This prompted a letter to be printed in prog 148 from Harry Harrison himself pointing out the error, for which he won £3.

These three stories were colorized and reprinted by Eagle Comics in 1985 and 1986 as a six-issue limited series. They were also collected in a trade paperback in July 2010 (ISBN 1906735514).