A Brief History of Time is based on cosmologist Stephen Hawking's 1988 bestseller of the same name. This anecdotal film concerns itself as much with Hawking's day-to-day life as it does with his unorthodox theories about the universe. Only the most close-minded viewer will be bothered by the ALS-suffering Hawking's physical appearance and his inability to move and speak without assistance (as narrator of the film, he utilizes a voice synthesizer, which he capriciously refers to as "my American accent"). Director Errol Morris inventively adopts a semi-dramatized approach to his interviews with Hawking's friends and relatives: they all appear in fabricated sets, and are lovingly photographed and lit as if they were starring in a film. Though of necessity a "talking heads" effort, A Brief History of Time is also cunningly and subtly cinematic.
~ Hal Erickson, All Movie Guide