One of the most exciting recent discoveries in astronomy is the existence of a huge variety of extrasolar planets orbiting other stars, including numerous multi-planet systems. Exoplanets can be very different to those found in our Solar System. This Priority Programme aims to explore such diversity and understand its origins. The programme wants to make substantial contributions to answering fundamental questions like „What does the diversity of exoplanets tell us about their formation processes and the evolution of planets and planetary systems?“