Piet Mondrian, one of the most significant representatives of modern abstract art, applied himself, aside from his own art work, to writing of theoretical texts. In his essays, he did not advocate for his own paintings, neither did he manifest any particular art movement. In these texts, one can trace rather general aesthetically-theoretical reflection on art, on the development of our world and on the position of a man in modern society. This thesis introduces Mondrian's comprehensive conception of art in light of aesthetics and the philosophy of art. It touches on the substance and function of art, on artistic means, on the role of an artist and on the meaning of art related to society and its development. The thesis focuses on the bases of Mondrian's theory and its influences. In addition, it presents various ideas of other contemporary avant-garde movements that somehow inspired Mondrian and that, together with his conception of art, create a certain context of the artistic atmosphere of the first half of the 20th century. The thesis draws from Mondrian's original texts that have, in most cases, not been translated into Czech, yet.

Après 1945, Auguste Herbin (Quiévy 1882 - Paris 1960) devient le maître en France de l’abstraction géométrique, une référence pour la seconde génération d’artistes abstraits, à la fois en Europe et dans le reste du monde. Les peintures d’Herbin réalisées à partir de son alphabet plastique, c’est-à-dire de 1942 à 1960 posèrent les jalons d’expérimentations nouvelles dans le domaine de l’art optique, de l’art cinétique, de l’art concret et de l’hard edge. La plupart des travaux réalisés par les artistes présents dans le Paris de l’après seconde guerre mondiale, tels Baertling, Agam, Dewasne, Vasarely, Soto, Fruhtrunk etc., n’auraient pu se concevoir sans la connaissance et l’assimilation du vocabulaire herbinien. Avait-on véritablement pris la mesure du rôle d’Auguste Herbin dans l’histoire et l’évolution de l’art abstrait ? / After 1945, Auguste Herbin (1882-1960) became the leading French abstract, geometric artist and an inspirational figure to abstract artists in both Europe and the Americas. Herbin’s Plastic Alphabet paintings are the forerunners of the wider experimentation in op’art, concrete art and hard edge painting. Much of the work by artists dominant in Paris in the 50’s and 60’s, such as Baertling, Agam, Dewasne, Vasarely, Soto, Fruhtrunk, is unimaginable without the advance wich Herbin represents.