Limitless is a 2011 American science fiction thriller film directed by Neil Burger and written by Leslie Dixon. Loosely based on the 2001 novel The Dark Fields by Alan Glynn, the film stars Bradley Cooper, Abbie Cornish, Andrew Howard, Anna Friel, and Robert De Niro. It follows Edward Morra, a struggling writer who is introduced to a drug called NZT-48 that greatly enhances his brain function, which helps him improve his lifestyle.

Limitless was released on March 18, 2011. Critical reviews were mixed-to-positive, and the film became a box-office success, grossing more than $161 million on a budget of $27 million. A television series covering events that take place after the film debuted in September 2015, running for one season.

Eddie Morra is a struggling author in New York City. His girlfriend Lindy, frustrated with his lack of progress and ambition, breaks up with him. Eddie encounters Vernon, the brother of his ex-wife Melissa, who gives him a sample of a new nootropic called NZT-48, which Vernon implies will help Eddie with his "creative problems". Eddie tries the drug and discovers that he has acquired perfect recall, able to analyze minute details and information at incredible speed. Under the influence, he helps his landlord's wife with her law school homework, sleeps with her, cleans his apartment, and, now inspired, makes major progress on his book.

Eddie visits Vernon's apartment to learn more about the pill, but finds him badly beaten. Vernon, refusing to explain what happened, sends Eddie to run some errands. When Eddie returns, he finds Vernon murdered and his apartment ransacked. Before the police arrive, Eddie finds Vernon's stash of pills.

Eddie finishes his book and fantasizes about what he can accomplish on the drug, but with little money, he decides to day trade with a $100,000 loan from Gennady, a loan shark. He makes shocking gains and resumes his relationship with Lindy. His success leads to a meeting with finance tycoon Carl Van Loon, who tests him by seeking advice on a merger with rival Hank Atwood's company. After the meeting, Eddie experiences an 18-hour dissociative fugue, which he refers to as a "time skip."

The next day, before a meeting with Van Loon, Eddie finds out that his drug supply has run out, forcing him to go without it. During the meeting, Eddie sees on a news telecast that a woman has been murdered in her hotel room. Recognizing her as a woman with whom he slept during his time skip, he abruptly leaves.

Eddie learns that everyone who took NZT-48 is either hospitalized or dead. He repays Gennady but Gennady steals one pill, and, after trying it, harasses Eddie for more. He and Lindy are also pursued by a man in a trench coat, and she tells Eddie that she cannot be with him while he is on the drug. Using pills that he stashed at Lindy's apartment, Eddie experiments and learns to control his dosage, sleep schedule, and food intake to prevent side effects. He hires a laboratory to reverse-engineer the drug, an attorney to keep the police from investigating him, and two bodyguards to protect him from Gennady.

On the day of the merger, Atwood falls into a coma. Eddie recognizes Atwood's driver as the man in the trench coat and realizes that Atwood was on NZT-48 and is suffering from withdrawal. While Eddie participates in a police lineup, his attorney steals his supply of pills. Eddie enters into withdrawal, and while Van Loon questions him about Atwood's coma, Eddie receives a parcel containing the severed hands of his bodyguards.