The Communication Book About the Author Mikael Krogerus (author) Mikael Krogerus is a Finnish journalist who works as an editor on Switzerland's biggest weekly magazine, das magazine. Roman Tschappeler (author) roman Tschappeler is a creative producer based in Biel, Switzerland, who produces documentary movies, ad campaigns and art installations. Krogerus and Tschappeler met at school in Denmark and have written four books together the question book, the test book, the change book and the international bestseller, the decision book.