Other films have told their stories backwards (the 1983 adaptation of Harold Pintner's "Betrayal" comes to mind) and many have used amnesia, but short term memory loss, as presented here, is a more frightening concept.
Intent on telling the story subjectively, in a way that mirrors Leonard's point of view, Nolan in effect constructed a despairing backward thriller, a film that starts at the end (a bit like Harold Pinter's "Betrayal") and works its way back to the beginning.
Playwright Harold Pinter used the same technique in "Betrayal" to show how an illicit affair destroyed the lives of the three people involved.
The idea of a narrative told backward was famously used by Harold Pinter in the 1983 film " Betrayal ," based on his play.
As in Harold Pinter's Betrayal, more and more crucial information is revealed as the story moves backward in time, scene by scene, to the beginning.