The World Without Us perspective. Chauncey Mabe of the "South Florida Sun-Sentinel" calls the book "one of the most satisfying environmental books of recent memory, one devoid of self-righteousness, alarmism or tiresome doomsaying". Tom Spears of the CanWest News Service concludes "it's more a portrait of ourselves, taken through an odd lens" and "[s]ometimes an obituary is the best biography". The book is categorized as non-fiction science but some commentators emphasize it may be better described as speculative fiction. "The World Without Us" is grounded in environmental and science journalism. Like other environmental books, it discusses the impact that the human race has had
The World Without Us write something that people would read ... without minimizing the significance of what's going on, nor trivializing it, nor oversimplifying it." Richard Fortey compares the book to the works of Jared Diamond, Tim Flannery and E.O. Wilson, and writes that "The World Without Us" "narrowly avoids engendering the gloom-and-doom ennui that tends to engulf the poor reader after reading a catalogue of human rapacity". Mark Lynas in the "New Statesman" noted that "whereas most environmental books sag under the weight of their accumulated bad news, "The World Without Us" seems refreshingly positive". Demonstrating the optimism on the grim subject matter