This document discusses three levels of cross-disciplinarity: multidisciplinarity, interdisciplinarity, and transdisciplinarity. Multidisciplinarity involves several disciplines addressing a topic without integrating their perspectives. Interdisciplinarity aims to integrate knowledge from different disciplines by developing new methodologies and approaches. Transdisciplinarity seeks to understand the world as a whole by going beyond individual disciplines and integrating them at a higher level of abstraction.