Short answers, pulled from the story.
Paul Schrader wrote the screenplay for Taxi Driver in under a fortnight during 1974. He drew inspiration from his own experience of chronic insomnia while battling life in New York City.
The final production cost reached $1.9 million after Columbia Pictures initially gave Scorsese a budget of $1.3 million. Robert De Niro, Cybill Shepherd, and Martin Scorsese received only $35,000 or less for their work on the film.
Robert De Niro lost 35 pounds to embody Travis Bickle and obtained a taxi driver's license before filming started. He repeatedly listened to a taped reading of the diaries of criminal Arthur Bremer and tape-recorded soldiers from the Midwestern United States for appropriate accents.
Taxi Driver formed part of the delusional fantasy of John Hinckley Jr. that triggered his attempted assassination of President Ronald Reagan in 1981. Hinckley stated that his actions were an attempt to impress Jodie Foster on whom he was fixated.
In 1994 the film was designated as culturally historically or aesthetically significant by the U.S. Library of Congress. It was selected for preservation in the National Film Registry.