S4 is a student-led training school aimed at students, early career researchers, and those who are new to applying speleothem science (the science of secondary cave mineral deposits) to reconstruct past climate, environmental and archaeological change. Following three successful previous summer schools (Heidelberg 2013, Oxford 2015, and Burgos 2017), we are excited to announce that the next S4 will be hosted by the 'Emil Racovita' Institute of Speleology (ERIS) and Babes-Bolyai University in Cluj-Napoca, Romania!