Alexander Selkirk was a real-life 18th-century castaway who was stranded for four years on an uninhabited island off the coast of Chile. He is generally thought to have inspired Defoe's Robinson Crusoe (source).
Daniel Defoe published a sequel to Robinson Crusoe the same year his novel debuted. In it, Crusoe travels all over the world to places like Madagascar and Siberia. The book's title? The Farther Adventures of Robinson Crusoe (source).
Daniel Defoe published his very first novel when he was 59 years old (source).
Before writing his most famous novel, Defoe tried his hand as a wholesale hosier. (That means he sold stockings. Glamorous? Not so much.) He also owned a factory and worked as a journalist (source).
In 1703, Daniel Defoe was arrested and put in the pillory for seditious libel. He not only wrote novels, but also satirical political pamphlets – some of which got him in big trouble (source).
Robinson Crusoe was a bestseller in 1719, the year it was published. Another bestseller from 1719? Eliza Haywood's Love in Excess.
Robinson Crusoe inspired a whole genre of island survival tales, known as Robinsonades. The genre is still alive and well today (see also: Castaway, Survivor, and Lost).
Don't believe us that Robinson Crusoe, published in 1719, was really all that popular? Here's some proof: "By 1895, 196 editions of Robinson Crusoe had been published, 114 revisions, 277 imitations, and 110 translations–translations in Dutch, Hebrew, Armenian, Bengali, Persian, and even Eskimo, to name a few" (source).