Short answers, pulled from the story.
Daniel Defoe is best known for Robinson Crusoe (1719), Moll Flanders (1722), and Roxana: The Fortunate Mistress (1724). Robinson Crusoe became one of the most widely published books in history and spawned a genre of imitation works called the Robinsonade.
Yes. Defoe worked as a spy for multiple political factions. He became a secret agent for King William III after 1689, and later Robert Harley, 1st Earl of Oxford, secured his release from Newgate Prison in exchange for intelligence work. He was sent to Edinburgh in 1706 to use underhand methods to influence Scottish opinion in favour of the Treaty of Union.
Defoe was convicted of seditious libel at the Old Bailey and sentenced to the pillory on the 31st of July 1703. The cause was his anonymously published pamphlet The Shortest-Way with the Dissenters (1702), which satirised calls to exterminate Protestant nonconformists so convincingly that authorities treated it as a genuine incitement. Judge Salathiel Lovell also imposed a fine of 200 marks and an indeterminate prison sentence.
The novel is believed to draw partly on the experience of the Scottish castaway Alexander Selkirk, who spent four years stranded in the Juan Fernandez Islands before being rescued in 1709 by Captain Woodes Rogers, whom Defoe knew personally. The island where Selkirk lived, Mas a Tierra, was renamed Robinson Crusoe Island in 1966.
Estimates vary widely. About 75 works can be confirmed under his own name or his acknowledged pen name. The scholar J. R. Moore attributed approximately 550 titles to Defoe, the largest count on record. Defoe used at least 198 pen names, and many works were published anonymously for decades after his death.
Defoe died on the 24th of April 1731 in Ropemakers Alley, London, not far from the Cripplegate parish where he was born. He was probably in hiding from creditors at the time. He was buried in Bunhill Fields, and a monument was erected there in 1870.