However, Sammy continued to administer the injections, and his wife died. Sammy's distraught wife repeatedly asked Sammy to administer her insulin shots for her diabetes, hoping he would remember and would stop himself from giving her a fatal overdose. After tests confirmed Sammy's inability to learn tasks through repetition, Leonard believed that his condition was at best psychological (and perhaps faked) and turned down his insurance claim. Leonard recalls Sammy Jankis, another anterograde amnesiac, from his insurance industry days.
Leonard investigates using notes, Polaroid photos, and tattoos to keep track of information he discovers. The police did not accept that there was a second attacker, but Leonard believes the attacker's name is "John G" or "James G". Leonard explains that he killed the attacker who raped and strangled his wife Catherine, but a second clubbed him and escaped. Leonard has anterograde amnesia and is unable to store recent memories, the result of an attack by two men. The black-and-white sequences begin with Leonard Shelby, a former insurance investigator, in a motel room speaking to an unseen and unknown caller. The film then continues, alternating between black-and-white and color sequences. As the sequence plays backward, the photo reverts to its undeveloped state, entering the camera before the man is shot in the head. The film starts with a Polaroid photograph of a dead man. In 2017, the United States Library of Congress deemed the film "culturally, historically, or aesthetically significant" and selected it for preservation in the National Film Registry. The film is now widely regarded as one of Nolan's finest works and one of the best films of the 2000s.
Memento received numerous accolades, including Oscar nominations for Best Original Screenplay and Best Film Editing. It was acclaimed by critics, who praised its nonlinear structure and motifs of memory, perception, grief, and self-deception, and it earned $40 million over its $4.5 million budget. Memento premiered at the 57th Venice International Film Festival on September 5, 2000, and was released in the United States on March 16, 2001. The two sequences meet at the end of the film, producing one complete and cohesive narrative.
The film's nonlinear narrative is presented as two different sequences of scenes interspersed during the film: a series in black-and-white that is shown chronologically, and a series of color sequences shown in reverse order (simulating for the audience the mental state of the protagonist). Carrie-Anne Moss and Joe Pantoliano co-star. He is searching for the people who attacked him and killed his wife, using an intricate system of Polaroid photographs and tattoos to track information he cannot remember.
Guy Pearce stars as Leonard Shelby, a man who suffers from anterograde amnesia, resulting in short-term memory loss and the inability to form new memories. The film's script was based on a pitch by Nolan's brother Jonathan, who wrote the 2001 story " Memento Mori" from the concept. Memento is a 2000 American mystery thriller film written and directed by Christopher Nolan, and produced by Suzanne and Jennifer Todd.