In his main work, The World as Will and Representation, first published in 1819, Schopenhauer presents his philosophy comprehensively and systematically.

In the first two of the four total "books" of the work, which are included in this first volume of the Greek edition, he initially addresses the object, composition, and limits of human knowledge (book I). He then discusses the essence of beings, the nature of reality (book II).

Human knowledge is defined by the a priori forms of the cognitive mechanism of the subject and is first conducted at the level of perception and then at the level of abstract knowledge. Our access to the essence of beings is provided by the immediate experience of will within us, which constitutes the metaphysical essence of reality.

The World as Will and Representation is undoubtedly one of the great classic works of European philosophy, having a significant influence on all areas of human thought. It incorporates a large part of the earlier philosophical tradition and serves both directly and indirectly as a very important source of modern philosophy.