Today is Roald Dahl Day 2019 - a special day to remember the author who wrote more than 20 children's books, including The Twits, Matilda and Charlie and the Chocolate Factory.
Many of them have been turned into films, including the BFG and Charlie and the Chocolate Factory.
He died on 23 November 1990. Every year, since 13 September 2006 - on what would have been his 90th birthday - there's been a special Roald Dahl Day to celebrate his stories and their characters.
Here are some fantastic facts about his life.
Roald Dahl was incredibly creative and came up with more than 500 new words and character names.
Such as the Oompa-Loopmas and scrumdiddlyumptious from Charlie and the Chocolate Factory, and snozzcumbers and frobscottle from the BFG.
He called his language Gobblefunk, and loved to play around with words and invent new ones or meanings.
Oxford University Press even created a special Roald Dahl Dictionary, featuring almost 8,000 real and imaginary words which he loved to use.
Roald Dahl spent around four hours every day writing stories from his garden shed!
He is said to have had a cosy old armchair and a specially designed writing board which would sit on his lap.
He would also only write his stories using a pencil and yellow paper.
James and the Giant Peach was almost called James and the Giant Cherry!
It was changed from a cherry to a peach because Dahl said a peach was "prettier, bigger and squishier than a cherry".
His original idea would have been for the giant cherry to be slowly pushed along a stream by water boatmen.
However, this was later changed to a giant peach which falls from the white cliffs of Dover.
Many of the characters and stories created by Roald Dahl were inspired by the people and places around him.
For example, Charlie and the Chocolate Factory was inspired by his childhood.
The chocolate maker Cadbury's used to taste-test their chocolate bars at Roald's school, and he used to dream that he would invent a new chocolate bar and win praise from Mr Cadbury.
The foxes' home in Fantastic Mr Fox was inspired by a huge tree which grew outside Roald Dahl's home in the village of Great Missenden, in England.
Roald even named one of the main characters in the BFG after his first grandchild - Sophie.
Before he became an author, Roald Dahl was a pilot for the Royal Air Force.
During World War Two, he flew a Hawker Hurricane plane.
Roald also became a spy for MI6 when he was recruited by the Canadian spymaster William Stephenson.
Dahl used to send them facts and secret information, and worked alongside Ian Fleming, who later became the creator of James Bond.
In 1943, Roald wrote his first official story aimed at children.
It was called The Gremlins and was inspired by his time as a pilot.
The story was about a bunch of naughty little creatures called Gremlins, who would cause all sorts of mechanical problems on aeroplanes.
It later become the inspiration behind the hugely popular film Gremlins, which was produced by famous Director Steven Spielberg in 1984.