Platero is the eponymous donkey of the 1914 children’s story Platero y yo (Spanish for Platero and I). The book is one of the most popular works by Spanish poet Juan Ramón Jiménez, the recipient of the 1956 Nobel Prize in Literature.
The Italian composer Mario Castelnuovo-Tedesco wrote the music of the stories.
Platero ("silvery") is described in the lyric prose of the book as a "small donkey, a soft, hairy donkey: so soft to the touch that he might be said to be made of cotton, with no bones. Only the jet mirrors of his eyes are hard like two black crystal scarabs." 
The little donkey remains a symbol of tenderness, purity and naiveté, and is used by the author as a means of reflection about the simple joys of life, memories, and various characters and their ways of life.