In August 2002 a massive flood struck the Czech capital city of Prague, inundating the collections of the National Library of the Czech Republic and the Prague Municipal Library. The librarians from these institutions and others in the Czech Republic had to respond quickly during a natural disaster. Despite the chaos and lack of preparation, Czech librarians and archivists were able to send a significant percentage of their flooded collections to be frozen, thus staving off immediate destruction of these historic collections by water or mold. Once the materials were frozen, librarians had to decide the best way to thaw and disinfect the items so that these materials could be used again. Influenced partly by cost, Czech librarians chose an experimental method over standard methods such as vacuum packing or vacuum freeze drying to treat the bulk of the frozen library materials. This essay traces the preservation decisions that librarians at two institutions, the National Library and the Prague Municipal Library, made during and after the flood to save their unique and historical collections.