The Wold Newton Family is like a big family tree of fictional people that were all created by different authors. Think of it like a big game of pretend where one author writes about one person, and then another author writes about another person, and so on.
The family tree starts with two real people, Sir Richard Francis Burton and his wife Isabel Arundell. But, in the make-believe world, their descendants include famous literary characters like Tarzan, Sherlock Holmes, and Philip Marlowe.
This family tree was created by a writer named Philip José Farmer, who thought it would be fun to connect all of these different characters together in a big story. It's kind of like a puzzle where he found ways to connect everyone together, like saying that Tarzan's parents were actually the siblings of Sherlock Holmes' grandparents.
Basically, the Wold Newton Family is just a big game of pretend that connects a lot of famous fictional characters together.