"We hold these truths to be self-evident, that all men are created equal..." This collection of essays addresses a philosophical problem raised by the first clause of these famous words. Does each signatory of the Declaration of Independence hold these truths individually, do they share some kind of a common attitude, or is there a single subject over and above the heads of its individual members that possesses a belief? "Collective Epistemology" is a name for the view that cognitive attitudes can be attributed to groups in a non-summative sense. The aim of this volume is to examine this claim, and to place it in the wider context of recent epistemological debates about the role of sociality in knowledge acquisition, in virtue and social epistemology, and in philosophy and sociology of science.