It's impossible for me to review this book without putting it the context of its classic predecessor. Probably I would not rate it so highly as a stand-alone book.
The fate of police inspector BZ Gundhalinu brought bittersweetness to end of THE SNOW QUEEN. If you care about the character, by all means read WORLD'S END. (Don't settle for the fractured summary found in THE SUMMER QUEEN.)
While reading THE SNOW QUEEN, I initially decided that I liked the officious technocrat Gundhalinu because of his unwavering support of his beleaguered commanding officer, Jerusha PalaThion. That BZ would expand his supporting role, undergo an intense personal upheaval, and emerge as a romantic renegade came as a delightful surprise. Even so, at the end of THE SNOW QUEEN, I assumed that BZ was an unfortunate bit of flotsam in the sibyl machinery's Greater Plan, and that the doors on his story had closed as tightly as the gate to Tiamat. I was happy to discover that Joan D. Vinge felt his journey worth continuing in WORLD'S END.
We catch up with Gundhalinu a few years later, burying himself in his police duties on the planet Four. Having experienced love on Tiamat did nothing to break the shackles of his Patrician background. BZ is still every bit the snob--defining nearly everyone--especially himself--according to the rigid terms of his hierarchical culture. And that culture judges him a coward and a failure.
More ghosts of the unresolved past surface when BZ's brothers, having squandered their aristocratic family's estates and good name, come to Four to seek their fortune in the notorious wilderness known as "World's End". They are presumed lost, and BZ embarks on what he assumes is a futile quest to set something right--to locate his brothers and perhaps regain his family's honor.
The quest is a Heart of Darkness-type journey, in which the increasingly surrealistic landscape reflects Gundhalinu's state of mind. A mysterious force in World's End creates disturbing anomalies in the harsh environment. As time passes, BZ succumbs to its maddening influence and loses his will to suppress his personal demons. At a shocking turning point, those demons are suddenly swept away as the demanding, insane consciousness behind World's End's anomalies invades BZ's mind. From then on he struggles to regain control and solve the mystery of this time- and space-defying wilderness.
The story is effectively told in the first person, through BZ's irregular journal entries. One can squirm experiencing the tumble towards insanity and the effort to return from the brink. The book is short, which saves it from becoming a wallow. But in spite of its brevity, it feels complete. A long, exhausting journey has taken place. Although the tone is unrelentingly grim, take heart! There is hope, enlightenment and rebirth at the end of the tunnel.