As in most of the other arts besides painting, most notably music and poetry perhaps, there has been a radical break between the classical periods of these arts, say from the 17th-late 19th centuries, and their modern period. The most significant aspect of this break has to do with the growing distance between the most advanced practitioners of these arts and their conceptual concerns and the wider, popular, public. Up until the second half of the 19th century there is a certain harmonious relation between the general public and the great art created within and for the public realm. But starting in th 1850's and perhaps a bit before there is a real break between the needs of the public and the interest of the artists. THese latter have been interested more and more in breaking the traditional rules of art, and in creating an art that is reflexive, that is, increasingly interested in its own modes of production, interrogating its own being being, rather than giving the public an image of its contemporary concerns. A growing alienation between public and arists have has been happening since that period (with the notable exception of film, the most recent of arts who remained for various reasons the only one inw hic the greatest works are potentially also the most popular and beloved. Due to this growing alienation between the public and the artists in all the major arts besides film, there has been developing an increasingly specialized vocabulary one NEEDS to learn in order to even start thinking and understanding what this modern art is about. General education is no longer enough to enable one to relate to the most advanced works of art. As such, the question of learning to appreciate modern art is indeed a crucial one, since one indeed needs to lean a specialized way of thinking and relating to things. Perhaps the best way to start would be a close study of Kant's Third Critique, which might be the most significant treatise theorizing the main question raised in the thinkng about he arts in the last two centuries (and one of the crucial dimensions of the complexity of modern art has to do precisely with the fact that, perhaps unlike previous art, it is essentially and intensely theoretical, that is, one cannot separate in relation to it theoretical issues "about" art, and so called simple appreciation of, and pleasure in, art). After Kant I would turn to a fewmore key philosophical works that were cruial to the development of a serious thinking about art, such as Nietzsche's the Birth of Tragedy, Heidegger's The Origin of the Work of art, Walter Benjamin's The Work of Art in the Age of Mechanical Reproduction, Merleu-Ponty's works on Cezanne, and Derrida's The Truth in Painting. I would then move on to read some famous art historians, Beginning perhaps with the works of Panowsky, Wolfflin, and Aby Warburg, and moving to contemporary critics such as Michael Fried, Rosalind Krauss, T.J Clark, and Georges Didi-Huberman. If you manage to cross this river, I think you will be on your way to understand the crucial issues that are at stake in the great works of the last hundred and fifty years.