The National Novel Writing Month (NaNoWriMo) is (despite its name) a huge international event during which hundreds of thousands of writers around the world seek to write a 50,000 word novel during the month of November. It began in the United States, but spread around the world. Nevertheless it has remained National Novel Writing Month as the brand was firmly in place. In fact so strong is the brand recognition that the non-profit organisation set up in 2005 to run it changed its name from the Office for Light and Letters to National Novel Writing Month.

The first National Novel Writing Month took place in July 1999 with a grand total of 21 participants and the following year it moved to November to avoid the distractions of fine summer weather. In that light it is probably unsurprising that one of the leading NaNoWriMo cities each year is Seattle, which is well known not only for a strong literary culture, but also for a lot rain. In 2014 over 300,000 people took part in what has become a major creative writing programme for both established and aspiring novelists. It also runs Camp NaNoWriMo in April and July each year when the rules are more relaxed: participants are not restricted to writing fiction and may choose their own target word-count.

Many novels have been published that began life during a NaNoWriMo, probably most famously Sarah Gruen's Water for Elephants, which was made into a blockbuster movie starring Robert Pattinson and Reese Witherspoon. Other well-known novels to come out of NaNoWriMo are Hugh Howey's Wool and Rainbow Rowell's Fangirl. In addition Mercia McMahon's first published novel Seattle in Shorts and first written novel Speaking of Men were written during National Novel Writing Month and Preserving Eternity was written during Camp NaNoWriMo.