306 FERDINAND KASSLERAS ONE OF THE MOST SIGNIFICANT FIGURES IN ARCHITECTUREOF LVIV IN PERIOD BETWEEN TWO WORLD WARS BOHDAN CHERKES https://orcid.org/0000-0001-5531-5374 Doctor of architecture, professor Director of Institute of architecture ANDRII SHTENDERA https://orcid.org/0000-0001-9451-4333 Postgraduate student Department of Design and Architecture Fundamentals Lviv Polytechnic National University Lviv, Ukraine Ferdinand Kassler, with more than 20 realized objects in Lviv, is one of the most influential architects of Western Ukraine in the interwar period. Lviv thanks its face to the European city in many respects his iconic buildings. The work of the galaxy of modernist architects on the territory of Ukraine, and F. Kassler in particular, was considered in the works of Y. Bogdanova, Y. Biryulov and S. Linda. The influence of F. Kassler's work on the development of modernist architecture on the territory of Ukraine and Eastern Europe cannot be overestimated. However, his architectural heritage has not yet been sufficiently investigated. The purpose of the study is to highlight the work of F. Kassler, its analysis in view of the significant influence not only on the further architecture of Lviv, but also the entire architecture of modernism in Ukraine. Scientific novelty is to highlight the influence of Kassler's creative work on the development of modernist architecture on the territory of Ukraine from 1910-1930.