What defines a true literary classic? Over the centuries, countless books have been enshrined in popular culture—whether through cinema or as required school reading. Some of the most famous classics, like “Moby Dick,” were panned upon first release, but now have become mainstays in first-year English classes. Old dystopian sci-fi works such as George Orwell’s “1984” and Margaret Atwood’s “The Handmaid’s Tale” never quite faded, but they both found new relevance in the tumultuous political climate after the 2016 election—and an Emmy-winning Hulu TV series for one of them.

These are the kinds of books an English teacher or a film buff might recommend as “must-read classics,” but that doesn’t necessarily mean people are reading them. After all, how many people do you know that have read “Moby Dick” for fun instead of for a school assignment? A book can be an artistic masterpiece, but to quote sci-fi luminary Ursula K. Le Guin, “The unread story is not a story; it is little black marks on wood pulp. The reader, reading it, makes it live: a live thing, a story.”

To see which books stand above the rest in terms of popularity and become great stories by Le Guin’s standards, Stacker researched book sales to create a definitive list of ultimate best-sellers—books that have sold at least 50 million copies worldwide since publication. Excluding religious, political, or ideological texts, this list covers 39 books that have reached this achievement, the overwhelming majority of which are fictional novels featuring stories that capture our imagination or change how we view the world.

From "Charlotte’s Web" to "The Da Vinci Code," read on to see which "Harry Potter" book sold more copies than any other book in the series, which mythical novel sparked a national phenomenon, and how many copies have been sold of one of the oldest modern novels of our time. Grab a cup of hot tea, cozy up in a blanket, and enjoy.

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Author: Anna Sewell
Year published: 1877
Approximate sales: 50 million

Written the year before she passed, English author Anna Sewell’s "Black Beauty" was an immediate success, although she did not live to see the book reach its fame. "Black Beauty" was Sewell’s only book and has sold an estimated 50 million copies worldwide.

Author: Johanna Spyri
Year published: 1880
Approximate sales: 50 million

A Swiss children's story about an orphan named Heidi that lives with her grandfather in the Swiss Alps, "Heidi’s Years of Learning and Travel" was written by prolific children's book author Johanna Spyri. 

Author: Lew Wallace
Year published: 1880
Approximate sales: 50 million

"Ben-Hur: A Tale Of The Christ" was a monumental work, quoted as "the most influential Christian book of the nineteenth century" in an article by editor Amy Lifson, published in a 2009 issue of Humanities magazine. The book has remained one of the best-selling American novels of all time; the film adaption starring Charlton Heston won 11 Academy awards. It was also the first ever novel to blessed by a pope, receiving the blessing from Pope Leo XIII.

Author: Lucy Maud Montgomery
Year published: 1908
Approximate sales: 50 million

Lucy Maud Montgomery’s novel is centered around the story of an orphan girl who is mistakenly sent off to work for two siblings who are looking for a young boy to help on their farm. The book follows the adventure of 11-year-old Anne Shirley as she makes her way through life on the farm. The book has sold over 50 million copies and has been adapted into a film, made-for-TV movies, and plays.

Author: Johnston McCulley
Year published: 1924
Approximate sales: 50 million

The original tales of Zorro were contained within a five-part series of stories published in All-Story Weekly. The tale by Johnston McCulley was eventually turned into a novel as "The Mark Of Zorro" only after the 1920 film adaptation’s commercial success. Based on the fictional adventures of a masked vigilante, "The Mark Of Zorro" inspired numerous Hollywood adaptations and TV series.

Author: Dr. Benjamin Spock
Year published: 1946
Approximate sales: 50 million

One of the few nonfiction books on the list, "The Common Sense Book of Baby and Child Care," written by Dr. Benjamin Spock, was an instant hit, selling 500,000 copies within six months of its 1946 release. The book was a favorite among post World War II mothers and was considered revolutionary at the time for its advice for mothers around trusting their maternal instinct.

Authors: E. B. White; illustrated by Garth Williams
Year published: 1952
Approximate sales: 50 million

E. B. White captured the imaginations of children everywhere with his seminal novel, "Charlotte's Web." The tale has been a mainstay in children's literature for over 60 years, telling the story of a pig named Wilbur and a heroic spider, Charlotte, that tries to save Wilbur from slaughter by writing messages in her web.

Author: Vladimir Nabokov
Year published: 1955
Approximate sales: 50 million

While covering some risqué subject matter, Russian American novelist Vladimir Nabokov’s "Lolita" has found significant commercial success. It has also received literary accolades as it was named one of the Modern Library’s 100 best books of the 20th century. Lolita was made into a film by famed director Stanley Kubrick in 1962.

Author: J. P. Donleavy
Year published: 1955
Approximate sales: 50 million

This landmark novel is set in Dublin and follows the promiscuous misadventures of a law student, Sebastian Dangerfield. Written by J. P. Donleavy, the novel was so racy that many publishers originally turned it down until a small publisher in Paris published it under their pornography imprint. This infuriated Donleavy, who would spend years trying to avenge the book and eventually sent his wife to buy Olympia Press out of bankruptcy at a public auction, returning the publishing rights to Donleavy.

Author: Gabriel García Márquez
Year published: 1967
Approximate sales: 50 million

Considered a godfather of the Latin literary movement of the 1960s and '70s, Gabriel Garcia Marquez’s "One Hundred Years of Solitude" was a groundbreaking work in Latin America's literary boom. Marquez’s novel is a work of fiction, but still critically examines momentous historical moments in Colombia's storied history.