This book continues where Speaker for the Dead left off. As the fleet approached Lusitania with the intent to blow up the planet, to avoid the spread of the descolada virus, the species on the planet, Bugger, Piggie and Human explore the nature of life and intelligence. And each faces the moral implications of Xenocide - the extermination of a species. 
 The characters are fascinating and the questions thought provoking. Occasionally though, the story gets bogged down in technical details. 
 In addition, a new colony world named Path is introduced, where THe "God=Spoken" play their own roles in the fate of another world. 
 I continue to enjoy this series