Stilfragen: Grundlegungen zu einer Geschichte der Ornamentik is a book on the history of ornament by the Austrian art historian Alois Riegl. It was published in Berlin in 1893. The English translation renders the title as Problems of style: foundations for a history of ornament, although this has been criticized by some. It has been called "the one great book ever written about the history of ornament."

Stilfragen: Grundlegungen zu einer Geschichte der Ornamentik is a book on the history of ornament by the Austrian art historian Alois Riegl. It was published in Berlin in 1893. The English translation renders the title as Problems of style: foundations for a history of ornament, although this has been criticized by some. It has been called "the one great book ever written about the history of ornament."