Beginning in the early 1920s, an early theory of Fremdenverkehr – a now obsolete term for tourism – emerged in the German-speaking world that dealt mainly with business and economic problems; since the 1960s, it has been replaced by the ever-expanding field of tourism studies. This gives many disciplines the space to approach the subject of tourism, or at least aspects of it, from their own particular academic perspective. Today, tourism studies means the multi-disciplinary bundle of academic approaches in the sense of an undisguised "transdiscipline