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". Genre 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 on the planet. Weisman's thought experiment removes the judgments and sufferings of humans by focusing on a hypothetical post-human world. This approach to the genre, which "throw[s] the spotlight on the earth itself", was found to be creative and objective. There have been other books that address similar topics, such as Gregory Benford's 1999 book Deep Time: How Humanity Communicates Across Millennia. Science fiction writers such as H. G. Wells (The War of the Worlds, 1898) and John Wyndham (The Day of the Triffids, 1951) had earlier touched upon the possible fate of cities and other man-made structures after the sudden removal of their creators. Similar parallels in the decay of civilization are detailed in 1949 post-apocalyptic science fiction novel by Berkeley English professor George R. Stewart, Earth Abides.Addressing his approach, Weisman said that eliminating the human element eliminated the "fear factor" that people are doing something wrong or that they will die; it is meant to be read as a fantasy, according to the author. Josie Appleton of Spiked related the book to "today's romanticisation of nature" in that it linked "the decadence and detachment of a modern consumerist society" with an ignorance of the efforts required to produce products so easily disposed. Appleton also felt the book countered the "Nature knows best" notion by highlighting the randomness of natural forces. Weisman's science journalism style uses interviews with academic and professional authorities to substantiate conclusions, while maintaining the "cool and dispassionate [tone]...of a scientific observer rather than an activist". Weisman said he purposely avoided the activist label: "Some of our finest science and nature writers only get read by people who already agree with them. It's nice to get some affirmation for whatever it is you believe is true, even if it's quite sobering, but I wanted to 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