New, fatal diseases started appearing at a vastly faster rate than ever before in the early 21st century, and a few centuries later, humanity has managed only to bring the death rate roughly in line with an increased birth rate again. Science has become a semi-military discipline; it's responsible for the defense of humanity against its greatest threat. Against this background, an expedition is sent to Titan, to study, it is hoped, pre-biotic conditions, and gain an understanding of biological principles from the base up. This may lead to the knowledge that will enable scientists to figure out what has caused the runaway explosion of disease.

The expedition consists of fifty people, both men and women, most of them suffering from one terminal disease or another. Twenty-one are still alive by the time they are in orbit over Titan and have their space station operational. This is where the story really starts, and most of the action is discussion. For the most part, the members of the expedition stay in sealed quarters, having no direct contact with each other, and only rarely venturing out physically to the surface of Titan. They operate equipment via waldoes and virtual reality.

All of this creates a sense of distance from both the action and the characters that's hard to shake. Titan is an interesting intellectual puzzle, and so, sometimes, are the motives of the characters, but I felt little sense of emotional involvement in their problems. Granted that one expects a Hal Clement book to emphasize the intellectual over the emotional; this book seemed significantly more tilted that way than, say, Mission of Gravity, or Iceworld, or Close to Critical. ( )

This book is long on science and engineering details but short on plot and character. ( )

Neither the scenario, nor the basic structure of the mission, nor the resolution feel particularly believable. Still, this book had potential to be pretty good--Clement gives us a reasonably interesting story that offers surprises and makes complex chemistry feel important. Unfortunately I never really cared about what happened to any of the large cast of largely undifferentiated characters. ( )