This book gives an extended argument for epistemic authority from the implications of reflective self-consciousness. Epistemic authority is compatible with autonomy, but epistemic self-reliance is incoherent. The book argues that epistemic and emotional self-trust are rational and inescapable, that consistent self-trust commits us to trust in others, and that among those we are committed to trusting are some whom we ought to treat as epistemic authorities, modelled on the well-known principles of authority of Joseph Raz. Some of these authorities can be in the moral and religious domains. The book investigates the way the problem of disagreement between communities or between the self and others is a conflict within self-trust, and argue against communal self-reliance on the same grounds as the book uses in arguing against individual self-reliance. The book explains how any change in belief is justified—by the conscientious judgment that the change will survive future conscientious self-reflection. The book concludes with an account of autonomy.