Saturday is a "post 9/11" novel, dealing with the change in lifestyle faced by Westerners after the 11 September attacks in the United States. As such, Christopher Hitchens characterised it as "unapologetically anchored as it is in the material world and its several discontents". "Structurally, Saturday is a tightly wound tour de force of several strands"; it is both a thriller which portrays a very attractive family, and an allegory of the world after 11 September 2001 which meditates on the fragility of life.
In this respect the novel correctly anticipates, at page 276, the July 7 2005 bombings on London's Underground railway network, which occurred a few months after the book was published:
London, his small part of it, lies wide open, impossible to defend, waiting for its bomb, like a hundred other cities. Rush hour will be a convenient time. It might resemble the Paddington crash – twisted rails, buckled, upraised commuter coaches, stretchers handed out through broken windows, the hospital's Emergency Plan in action. Berlin, Paris, Lisbon. The authorities agree, an attack's inevitable.
The book obeys the classical unities of place, time and action, following one man's day against the backdrop of a grander historical narrative – the anti-war protests happening in the city that same day. The protagonist's errands are surrounded by the recurring leitmotif of hyper real, ever-present screens which report the progress of the plane and the march Perowne has earlier encountered. Saturday is in tune with its protagonist's literary tastes; "magical realism" it is not. The 26-hour narrative led critics to compare the book to similar novels, especially Ulysses by James Joyce, which features a man crossing a city, and Virginia Woolf's Mrs. Dalloway, of which Michiko Kakutani described Saturday as an "up-to-the-moment, post-9/11 variation."
The novel is narrated in the third person, limited point of view: the reader learns of events as Perowne does. Using the free indirect style the narrator inhabits Perowne, a neurosurgeon, who often thinks rationally, explaining phenomena using medical terminology. This allows McEwan to capture some of the "white noise that we almost forget as soon as we think it, unless we stop and write it down." Hitchens highlighted how the author separates himself from his character with a "Runyonesque historical present ("He rises …" "He strides …") that solidifies the context and the actuality."