Since it was announced in September 2018 there has been a great deal of coverage around Plan S – the new initiative for Open Access publishing. The plan calls for all scientific publications resulting from grants funded by public research to be made available on compliant journals or platforms. This decision has drawn both praise and alarm from the research community but what does it all mean? This webinar will discuss the history of Plan S, the principles that make up the plan and the arguments both in favour and against.