From this angle, the book explores 'diffraction', which has begun to impact critical theories and humanities debates, especially via (new) materialist feminisms, STS and quantum thought, but is often used without further reflection upon its implications or potentials. Doing just that, the book also pursues new routes for the onto-epistemological and ethical challenges that arise from our experience of the world as relational and radically immanent; because if we start from the ideas of immanence and entanglement, our conceptions of self and other, culture and nature, cultural and sexual difference, our epistemological procedures and disciplinary boundaries have to be rethought and adjusted. The book offers an in-depth consideration of 'diffraction' as a quantum understanding of difference and as a new critical reading method. It reflects on its import in humanities debates and thereby also on some of the most inspiring work recently done at the crossroads of science studies, feminist studies and the critical humanities. This book was originally published as a special issue of Parallax.