The Institute of Molecular Genetics of the ASCR organised an international conference that brought together approximately 180 scientists from 20 countries whose study is focused on diverse aspects of the biology of different retroviral and retrotransposon systems. Sharing their individual insights and specific expertise should not only serve to uncover some of the remaining gaps in society’s understanding, but may also highlight important basic principles and properties that are unique to these elements and their interactions with their hosts. and Jiří Hejnar.