“Write what you know,” they say. So it makes sense that many authors take a good look around at friends and family when creating characters for their books.

1. Mark Twain once admitted that he wasn’t terribly creative in creating Huckleberry Finn – he based the character almost precisely on his childhood friend Tom Blankenship. From his autobiography:

“In Huckleberry Finn I have drawn Tom Blankenship exactly as he was. He was ignorant, unwashed, insufficiently fed; but he had as good a heart as ever any boy had. His liberties were totally unrestricted. He was the only really independent person—boy or man—in the community, and by consequence he was tranquilly and continuously happy and envied by the rest of us. And as his society was forbidden us by our parents the prohibition trebled and quadrupled its value, and therefore we sought and got more of his society than any other boy’s.”

Sadly, according to the editor’s notes in Twain’s posthumous autobiography, Blankenship was repeatedly arrested for theft and died just five years after Huckleberry Finn was published.

2. When Jack Kerouac wrote On the Road, he was really writing about his own cross-country exploits with his Beat Generation buddies. For example, the selfish Dean Moriarty represents Neal Cassady, close pal of Kerouac, Allen Ginsberg, Ken Kesey and the Grateful Dead (among others). In fact, the character’s name is Neal in the original On the Road scroll. But that’s not the only character Cassady inspired: Kesey, Hunter S. Thompson, and Tom Wolfe all took inspiration from Cassady.

The real Neal died at the age of 41 after being found comatose by a railroad track in Guanajunto, Mexico, in 1968.

3. Even as one of the wittiest female characters in literary history, Nora Charles from The Thin Man doesn’t hold a candle to her inspiration, Lillian Hellman. Lillian was author Dashiell Hammett’s lover for 30 years, but she was also a respected playwright, screenwriter, author and outspoken political activist. Hammett apparently told Hellman that she was the inspiration for his female villains as well.

4. It’s almost hard to imagine that the furious and completely insane jilted bride of Charles Dickens’ Great Expectations has a flesh-and-blood counterpart. But she does – in fact, there are at least three that might fit the bill.

Real-life Miss Havisham #1: Eliza Emily Donnithorne, an Australian woman who thought she was getting married in 1856. When she was stood up by the groom, she refused to change anything about the house; the wedding feast even sat out until it rotted into non-existence. Legend has it that Donnithorne never left the house again.

Potential Havisham #2: Elizabeth Parker. This Shropshire, England, woman was also jilted on her wedding day and became quite reclusive afterward. Dickins was known to visit Shropshire, and the fact that Miss Parker’s house was called Havisham Court seems like it must be more than coincidence.

Havisham the Third: Madame Eliza Jumel, Aaron Burr’s second wife. It’s said that Jumel may have gone a little crazy in her desperate attempts to break into New York high society; after finally throwing a successful dinner party for Joseph Bonaparte, she supposedly left the banquet and place settings out for decades to commemorate her social acceptance.

5. The wealthy Philomena Guinea of Sylvia Plath’s The Bell Jar was based on Plath’s own rich benefactor, Olive Higgins Prouty. Prouty was a novelist probably best known now for Now, Voyager.

6. The modest grave of Elizabeth Pain in Boston’s King’s Chapel Burying Ground holds a secret if you look at it closely. Some believe the “A” inscribed on the stone shows that she was “whipt with twenty stripes,” though it was for the murder of her child, not for adultery. She was found innocent, by the way, but received the punishment anyway – even in death. The damning mark may have served as inspiration for The Scarlet Letter author Nathaniel Hawthorne. There’s also a record of one Hester Craford who was severely flogged for “fornication” with a man named John Wedg in 1669. At the very least, Hawthorne may have borrowed her name.

7. As a neighbor of the Alcott family in Concord, Mass., Elizabeth Hoar served as the model for Beth March in Little Women. Hoar was also good friends with Henry David Thoreau and Ralph Waldo Emerson, who liked to call her “Elizabeth the wise.”

8. The character of Ford Prefect isn’t based on a real-life person, exactly, but a real-life object. Douglas Adams once explained that his Hitchhiker’s Guide to the Galaxy alien had “skimped a bit on his preparatory research” of Earth and thought he was choosing an inconspicuous name for himself. Adams later explained further, saying that Prefect saw vehicles swarming the streets of our little planet and “had simply mistaken the dominant life form.” The Ford Prefect, by the way, was a British car produced from 1938-1961.

9. Yes, Virginia, there really was a Severus Snape, and his name was almost as wizardy: John Nettleship. Nettleship was J.K. Rowling’s own teacher, perhaps one she didn’t enjoy very much based on this description of Snape:

“Snape is the very sadistic teacher loosely based on a teacher I myself had, I have to say. Children are very aware and we’re kidding ourselves if we don’t think that they are – that teachers do sometimes abuse their power and this particular teacher does abuse his power. He is not a particularly pleasant person at all.”

Nettleship wasn’t thrilled with the comparison when he found out about it, saying, “I knew I was a strict teacher but I didn’t think I was that bad.” He later came to terms with it enough to write a book called Harry Potter’s Chepstow about various locations from Rowling’s school days that may have inspired people and places from her successful series. Nettleship died of cancer last year.

10. Anyone who has had a younger sibling they considered evil can probably relate to Eoin Colfer’s inspiration for Artemis Fowl. His little brother, Donal, was “a mischievous mastermind who could get out of any trouble he got into,” and seeing a picture of Donal in a dapper first communion suit reminded Colfer of a tiny James Bond villain.