With any long-running series, there's always a concern about whether the latest book (or movie) will be a good one or one of the duds. James Bolivar `Slippery Jim' diGriz made his first appearance in a 1957 short story, so he's been around longer than most. The books in the series vary in tone from the dark (The SSR's Revenge) to almost pantomime comedy (the brilliant SSR Wants You), and there's always a thought-provoking undercurrent, where the author riffs on politics, philosophy, capitalism, equality, or whatever.
For me there's only one dud in the series, The SSR Goes to Hell, and I should probably read that one again before condemning it completely. Five star books in the series are the original novel, The Stainless Steel Rat, plus SSR Saves the World (time travel and a Napoleonic villain), SSR Saves the World (aliens invade our universe, and Jim flirts with them!), SSR is Born (the prequel), and SSR Joins the Circus.
The latest, the Stainless Steel Rat Returns, isn't quite a five star entry, but it has many of the qualities of the best of them. The plot draws the original stories and the `prequel' stories together, as Jim is visited by cousins from his rural home planet who bring with them a herd of porcuswines. As with most of the rest of the series, the plot consists of a series of catastrophes and hairbreadth escapes, building to the final confrontation. Along the way Harrison takes a few swipes at the banking system and the human race's ability to start a conflict over just about any kind of difference between two groups. The only thing really missing is the trademark Slippery Jim bank heist or theft.
The first time through I read this at a greedy gallop because I wanted to find out what happened next. A second reading allowed me to savour the best bits. And I've just heard a snippet of the audio book, which sounds great, so I'll be picking that up too. So this book's probably a three or a four, and I'm giving it four stars because I'm glad to see the Rat back.