Mazovian Museum in Plock, which specializes in the art trend at the turn of the 20th century, known as Art Nouveau, has established an autonomic collection of applied decorative arts, i.e. art déco. The efforts of the Museum so far in obtaining interesting objects of high artistic value, both from the Western Europe and Poland, focused on utility and decorative art representing architecture, interior design and crafts dating back years 1925 – 1939. This unique and best collection in Poland includes original furniture of Polish, German and French designers, decorative and utility materials, pieces made of glass, ceramics, colourful metals, jewellery, fashion and numismatic objects (medals, posters), graphics and sculpture. The new era, named as art déco no early than in the 1960s, started in Paris between great worldwide crises in years 1922 – 1932 as a diverse artistic phenomenon. Its origins are directly connected with Art Nouveau, the ideas, concepts and trends dating back year 1890 in England and the opposition against historic styles reinstated in the 19th century. Art déco was the next following historic Secession, natural continuation of the pursuits of the new generation associated with the artistic milieus of the modern and avant-garde Europe of the in-between-wars era.