“A guy walks into a bar…” is a typical form of what has been called the “bar joke.” A version involving author Charles Dickens (1812-1870) and his novel Oliver Twist (1837-9) is:
 
“Charles Dickens walks into a bar and orders a martini. The bartender asks, ‘Olive or twist?’”
 
The joke has been cited in print since at least 2000. “Shakespeare walks into a bar…” is another bar joke that involves an English author.
 
   
Wikipedia: Charles Dickens
Charles John Huffam Dickens (/ˈtʃɑːrlz ˈdɪkɪnz/; 7 February 1812 – 9 June 1870) was an English writer and social critic. He created some of the world’s best-known fictional characters and is regarded as the greatest novelist of the Victorian era. His works enjoyed unprecedented popularity during his lifetime, and by the twentieth century critics and scholars had recognised him as a literary genius. His novels and short stories enjoy lasting popularity.
 
Wikipedia: Oliver Twist
Oliver Twist, or The Parish Boy’s Progress, is the second novel by Charles Dickens, and was first published as a serial 1837–9. The story is of the orphan Oliver Twist, who starts his life in a workhouse and is then sold into an apprenticeship with an undertaker. He escapes from there and travels to London where he meets the Artful Dodger, a member of a gang of juvenile pickpockets, which is led by the elderly criminal Fagin.
 
Google Groups: alt.food.wine
Here is a bar cheat sheet
Shel Talmy
7/23/94
BAR CHEAT SHEET
** All drinks are 1 shot per, unless stated otherwise.
(...)
LITTLE DICKENS IS A MARTINI WITH AN OLIVE OR TWIST
 
Google Groups: alt.support.shyness
a.s.s UK meet
lm
12/12/00
(...)
Charles Dickens walks into a bar and orders a martini. The bartender says, “Olive or Twist?”
 
Google Books
A Prairie Home Companion
Pretty Good Joke Book
By Brian Becker
Minneapolis, MN: HighBridge
2003
Pg. 115:
Charles Dickens walks into a bar and orders a martini. The bartender asks, “Olive or Twist?”
   
Google Books
The Martini Book:
201 Ways to Mix the Perfect American Cocktail
By Sally Ann Berk
New York, NY: Black Dog & Leventhal Publishers, Inc.
2007
Pg. 72:
Charles Dickens walks into a bar and orders a martini.
 
The bartender asks, “Olive or twist?”
 
Twitter
Vikram
‏@V1kram
Charles Dickens walks into a bar and orders a martini. The bartender asks, “Olive or twist?”
1:27 AM - 6 Jan 2008
   
Google Books
The Mammoth Book of One-Liners
By Geoff Tibballs
London: Constable & Robinson Ltd
2012
Pg. ?:
Charles Dickens walks into a bar. The bartender says: “Olive or twist?”
 
reddit
Charles Dickens walks into a bar… (self.Jokes)
submitted September 24, 2015 by HolyHypodermics
and orders a Martini. The bartender asks,“Olive or twist?”