Factores de deterioro en colecciones documentales: el caso de la colección “Julián del Casal” en la Biblioteca Nacional de Cuba.

The work carried out in the Julián del Casal fund, belonging to the Manuscript Area of the Cuban Collection of the National Library of Cuba José Martí (BNCJM), is described. The deterioration factors of said documentary collection are identified. All with the purpose of guaranteeing its preservation