Is the movie A walk in clouds made from a book?

Yes, the movie "A Walk in the Clouds" is based on a book, but not a novel. It's based on a short story by Luis Valdez, who also wrote the screenplay for the movie.

The short story is titled "The Cisco Kid" and was originally published in 1986. It's a different story than the novel "Cisco Kid" by O. Henry, but it shares the name and the protagonist.

The movie adaptation changed the title to "A Walk in the Clouds" and expanded upon the short story to create a more substantial narrative.