Science festivals: do they succeed in reaching beyond the ‘already engaged’?

The cultural phenomenon of 'science festivals' is ever expanding throughout the world, as universities, city and regional governments, and science engagement professionals alike embrace the concept of a focused 'celebration' of science. In the past however science festivals have been criticized for neglecting underrepresented audiences. This special issue explores the extent to which current science festivals have managed to engage with diverse publics, and identifies the key challenges facing the future of science festivals, most notably the need for deeper research into the impacts of science festivals.