|The opening shot of Blade Runner defined futuristic dystopia for a generation or more.|
Do Androids Dream of Electronic Sheep (1968)
by Phillip K. Dick
Do Androids Dream of Electronic Sheep gained it's canonical status retroactively, after the 1982 film Blade Runner became a genre-defining hit. Before Blade Runner struck a chord in the psyche of the world, Dick was considered a second-tier genre-limited author of ambitious science fiction. Afterwards, he became a prophet of "cyber punk" and the computer age. Today, it's impossible to read Do Androids Dream of Electronic Sheep independent of one or multiple viewings of Blade Runner. The biggest difference between book and film is the religious element in the book, which is absent from the film.
That religion is called Mercerism, and it is the least original element in the book. It bears a striking to resemblance to other sci-fi/future religions like the Church of All Worlds (from Stranger in a Strange Land by Robert Heinlein), Bokonism, from Cat's Cradle by Kurt Vonnegut, and of course Scientology, which as much a creation of a 50's era science fiction writer as any of the others. On the other hand, Dick's depiction of a post-nuclear war San Francisco (changed to Los Angeles in the movie) and an Earth deserted by all but the most pathetic human specimens, called "specials" or "chickenheads" in the argot of the book.
The largest difference between book and film is the question of whether Deckard, the bounty hunter/blade detective-hero is android or human. The book is unambiguous that Deckard is human. The movie suggested that Deckard was perhaps an android, which apparently was the perspective of director Ridley Scott. The film is far superior in depicting the environment. Other than conveying the sense that the Earth was quasi-abandoned in drowning in it's own debris, the book does little to convey the world of Blade Runner/Do Androids Dream of Electric Sheep the way film does so memorably.