This book is the first book, though third story, in the ConSentiency Universe. In this Universe, the wheels of democratic-government run so efficiently, so well, that laws are created, discussed, and passed in a matter of hours. You could imagine where this could be a bad thing (James Madison sure did, this is the ultimate Madisonian-nightmare). In lieu of the bureaucratic red tape to prevent society from doing ill-thoughtout things like passing bad laws, the ConSentiency created the Bureau of Sabotage (BuSab). It's best agent? Jorj X. McKie, Saboteur Extraordinaire, and the main character.
This book, in particular, is about the Caleban. A race that offered the other sentient races a means of travel through a "jumpdoor" to virtually anywhere in the galaxy. Without thinking of any consequences, the government agreed. This had the unknown effect of essentially linking everyone to the Caleban. So if one Caleban died (they are apparently immortal otherwise)... everyone who had used that Caleban's jumpdoor dies or goes utterly insane. Through some social norms, legal contracts, and other contractual issues, a Caleban comes under the control of the main villain. This contracts allows the Caleban to be whipped to death.
McKie needs to find a way to save the last Caleban. Unfortunately, this falls beyond the scope of BuSab's stated mission. While it can take action to stop government... it cannot take action against a private citizen. Therein lies of the dilemma.
So, it's a story about bureaucracy, the need for checks and balances, and laws. Very different from Herbert's other works. There's a strange emotional plot involved between McKie and the last Caleban (which is essentially a star as that is their visible manifestation) that makes for more intrigue. It's intriguing but not nearly as serious as Herbert's later work in the ConSentiency Universe: The Dosadi Experimet (Mass Market Paperback)