Bill Bergson Lives Dangerously (original Swedish title: Mästerdetektiven Blomkvist lever farligt) is a 1951 Swedish novel written by Astrid Lindgren. It's the 2nd book about the Master Detective Kalle Blomkvist. In this book the Rövarspråket ("Robber Language") appears for the first time and is very popular until present. According to the book, Eva-Lotta's father Master Baker told her when he and his friends spoke Rövarspråket as boys. Source: Wikipedia (en)