Ežens Laube, one of the most outstanding Latvian architects of the first part of the 20th century, was engaged in architectural practice, education, theory and public realm. Over the 60 years he had published 40 theoretic papers and two books. His treatise written in English “Manifestation of Architecture” remained unpublished. Laube’s main interest is fundamental theoretic cognition themes, among them, essence, contents and boundaries of architecture. Fusing together Kantian philosophy, Christian ethics and worldview of an artist in a uniform cognition method, he defines architecture as spiritual and practical human discipline, manifesting itself in shaping of human life space and in creative cognition what extends comprehension of reality. Laube considers integral knowledge and skills, experience, colorful personality, ethics, imagination, humanism to be requisite qualities of an architect, but self-realization to be the major task of human life. Wholeness and harmony he promotes to be the main quality of architecture. Laubes design method could be named as method of particular task, in creation process seeking for means of expression able to define the essence of realizable object unmistakably. Theory of architecture, for him, is the integral, direct part of architectural practice that expresses itself as theory based, conscious design methods. Laube’s contribution regarding specific professional themes is outstanding as well. He analyzed ever constantly topical theme of “language” of architecture and its meanings in the context of stylistics. His statement is that style generates from the complexity of different circumstances. Laube focused upon national architectural style problems that was one of the main theoretic items during the 1930-s. He was critically disposed towards modern architecture, but his criticism often was so precise that, ahead of his time, he predicted the oncoming modern architecture crisis and indirectly outlines the routes to overcome it. Laube reviewed such aspects of architecture’s language as tectonics, composition, buildings typology and aesthetics as well. Laube’s heritage in Latvian architectural theory is unique in scale, scope and contents.