Editorial Valdemar is an independent publisher based in Madrid, specializing in publishing classics of gothic fiction, fantasy literature, science fiction and horror literature, among other genres.

Founded in 1989 by Rafael Diaz Santander and Juan Luis Gonzalez, accumulated a backlist of more than six hundred titles, most of them international references in the narrative genre, carefully translated by some of the best specialists in Spain, as Mauro Ermine, Francisco Oliver Torres, Juan Antonio Molina-Foix, José María Nebreda, Marta Lila Murillo, and Oscar Palmer. Especially in its catalog to include the complete works of H. P. Castilian Lovecraft, the canon of Sherlock Holmes, the works of Bram Stoker and Marcel Proust, or full stories of Robert Louis Stevenson.

After a quarter century of existence, the label has been introduced in the contemporary horror literature cutting through the collection Insomnia where works have been published Anglo-Saxon authors like Caitlin R. Kiernan, Graham Masterton and Jack Cady, and the Spanish Emilio Bueso.

Valdemar distributes its books in Spain and, through specialized bookstores and distributors of imported goods in Chile, Colombia, Costa Rica, Mexico, Puerto Rico, Peru, Uruguay and Venezuela.