In this book Carlos Jurado describes his relationship with the camera obscura and the art of capturing images. By rewriting the history of the camera obscura and narrating the use of the unicorn's horn in the creation of photography, Jurado sheds light on the rationale behind his own technique.

His handcrafted pinhole cameras made of cardboard are inspired by the centuries-old technique of capturing images by using magical boxes (camera obscura), but he employs modern materials to create his photographs.

The book El arte de la aprehensión de las imágenes y el unicornio (The Art of Capturing Images and the Unicorn) was first published in 1974 by the Universidad Nacional Autónoma de México (National University), in an edition of 1 000 which sold out that same year. A second edition of 300 copies was handmade using serigraphy in the Leñateros Workshop in Chiapas, Mexico in 1998.