Haus Wittgenstein, the exhibition that inspired this book, addresses the complex singularity of a house designed by Ludwig Wittgenstein (1889–1951), a famous, eccentric and intense philosopher, in a Vienna that was not only experiencing a “joyful apocalypse”, according to Jean Claire, but was also celebrating “the man without qualities”, as Robert Musil put it. Thanks to a historical, cultural and architectural singularity, it is not possible to fit this project into any place in the history of architecture, philosophy or art. Its authorship is also a source of debate, since the project began with a discussion with the architect, Paul Engelmann, who later handed it over to the philosopher, who subsequently added the details, built it and instilled in it a unique spirit and character.