Nathaniel Hawthorne's Anne of Green Gables

Here is a text from one of my best friends:

"Some girl at Pilot Light was just nice enough to explain how Nathaniel Hawthorne penned BOTH House of the Seven Gables and its sequel, Anne of Green Gables."

Did you know that Nicolo Machiavelli wrote both The Prince AND its sequel, Harry Potter and the Half-Blood Prince?

How about Fitzgerald's The Great Gatsby and its prequel, The Great Gilly Hopkins?

Not to mention Van Vogt's embarrassing attempt at following Slan with the Star Trek tie-in WLAN Systems & Wireless IP for Next Generation Communications