MADRID — Carlos Ruiz Zafón, whose mystery novel “The Shadow of the Wind” became one of the best-selling Spanish books of all time, died on Friday at his home in Santa Monica, Calif. He was 55.

His death was announced by his Spanish publishing house, Planeta. His literary agent, Antonia Kerrigan, said the cause was colon cancer, which he had been battling for two years.

Published in 2001, “The Shadow of the Wind” was translated into dozens of languages and has sold more than 15 million copies worldwide. It was the second-most-successful Spanish novel after Miguel de Cervantes’s masterpiece “Don Quixote,” according to Planeta.

A visit to a book warehouse in Los Angeles, where he moved in the 1990s, inspired Mr. Ruiz Zafón to write “The Shadow of the Wind,” but he set the action in his birthplace, Barcelona. Written as a story within a story, the novel crisscrosses the tumultuous decades before, during and after the Spanish Civil War of the 1930s.

It starts in 1945, when a boy named Daniel Sempere is taken by his father to a mysterious place known as the Cemetery of Forgotten Books, where Daniel selects a book called “The Shadow of the Wind.” Fascinated by its obscure author, Julián Carax, Daniel enlists the help of friends to investigate the writer’s past, which also brings up the disturbing story of a character who has been burning all the copies of the book he can find.

Reviewing “The Shadow of the Wind” for The New York Times in 2004, when it was first published in English (translated by Lucia Graves), Richard Eder wrote that even though it was generally “lowdown and lazy” to compare writers, Mr. Ruiz Zafón’s work could have been publicized as “Gabriel García Márquez meets Umberto Eco meets Jorge Luis Borges for a sprawling magic show, exasperatingly tricky and mostly wonderful.”

Other critics praised Mr. Ruiz Zafón for seeking to transpose the pace and the colorful characters of great 19th-century novels, notably Dickens’s, into a 20th-century context and writing style.

The novelist Stephen King wrote: “If someone thought that the genuine Gothic novel had died in the 19th century, this book will change their mind. This is a novel full of splendor and hidden trapdoors in which even the subplots have subplots.”

Carlos Ruiz Zafón was born on Sept. 25, 1964, in Barcelona. His father worked for an insurance company, and his mother was a homemaker.

He attended a Jesuit school and then studied information technology. After working in advertising, he decided to pursue his passion for literature full time.

His debut novel, “The Prince of Mist,” published in 1993, was written for a teenage audience and won him the first of many literary awards.

In an essay on his website, Mr. Ruiz Zafón explained: “I have written for young readers, for the movies, for so-called adults; but mostly for people who like to read and to plunge into a good story. I do not write for myself, but for other people. Real people. For you.” He concluded, “I became a writer, a teller of tales, because otherwise I would have died, or worse.”

“The Shadow of the Wind” was the first work in a four-part project he called “The Cemetery of Forgotten Books,” which he completed in 2016 with the publication of “The Labyrinth of Spirits.” Ms. Kerrigan, his agent, said his long fight against cancer cut short his plans to write more novels, as well as film scripts.

When he sent her the manuscript of “The Shadow of the Wind,” Ms. Kerrigan recalled in a phone interview, “Carlos had been very successful with his young-adult books, and he had no real need to switch to an adult novel. But authors sometimes want to enlarge their vision of the world, and he clearly felt the time had come for him to do just that.”

“The Shadow of the Wind” was not an immediate hit, Ms. Kerrigan said, and this led to some tensions with his publisher, which wanted to reprint it quickly in paperback to help jump-start sales. But about six months after its release, she said, after some good reviews, “Christmas came and it finally took off.”

On Friday, Prime Minister Pedro Sánchez of Spain paid homage on Twitter to Mr. Ruiz Zafón, calling him “one of the most read and admired Spanish authors worldwide” and adding, “Thank you for letting us travel through your stories.”

Mr. Ruiz Zafón is survived by his wife, Mari Carmen Bellver.

Mr. Ruiz Zafón’s hobbies included collecting items related to dragons, with which he felt he had much in common. “We are creatures of the night, not very sociable, we dislike wandering knights and are difficult to get to know,” he wrote on his website.

In recent decades, Mr. Ruiz Zafón had split his time between Barcelona and Los Angeles, to which he had been drawn in part because of his childhood fascination with Hollywood.

The success of “The Shadow of the Wind” inspired guided tours of Barcelona, during which visitors trace the footsteps of the book’s characters. Speaking to The Times last year, Mr. Ruiz Zafón offered his own Barcelona tourism recommendations, including the Montjuïc cemetery where he once almost got locked in as a teenager.

“I still love the place,” he said, “no matter how creepy it is.”