"These 28 letters are impregnated with a passion for painting; more concretely, for the painting craft: this is what Luis Caballero seeks in museums, what he is unable to find in the paintings he encounters in Parisian galleries, what he affectionately envies in his correspondent. But perhaps the deepest aspect, the most revealing of the passion that infuses the letters, is Caballero´s permanent introspection regarding his work. Thus, for example, the confusion of someone intent on learning, a young man who will in time become one of Colombia´s foremost draftsmen and who wrote, before turning twenty: 'Here I am in despair at not learning to draw, but that is the least of my problems, I will eventually learn, I am certain of that; but there are moments when I am filled with anguish and discouragement by not being able to do what I want to do. It is terrible. It is terrible to hold in my head the most extraordinary paintings, knowing that I am incapable of painting them. My consolation is to think that my problem is that I don´t yet know how to draw, and that I will eventually learn. Silliness, I am begining to think that I wll never be able to paint. It is too difficult.'".