Roman Tschäppeler is a creative producer based in Biel, Switzerland, who produces documentary movies, ad campaigns and art installations. Krogerus and Tschäppeler met at school in Denmark and have written four books together - The Question Book, The Test Book, The Change Book and the international megaseller, The Decision Book, twice the bestselling UK business book of the year.

Roman Tschäppeler is a creative producer based in Biel, Switzerland, who produces documentary movies, ad campaigns and art installations. Krogerus and Tschäppeler met at school in Denmark and have written four books together - The Question Book, The Test Book, The Change Book and the international megaseller, The Decision Book, twice the bestselling UK business book of the year.

Roman Tschäppeler is a creative producer based in Biel, Switzerland, who produces documentary movies, ad campaigns and art installations. Krogerus and Tschäppeler met at school in Denmark and have written four books together - The Question Book, The Test Book, The Change Book and the international megaseller, The Decision Book, twice the bestselling UK business book of the year.