Many of Søren Kierkegaard's most controversial and influential ideas are more relevant than ever to contemporary debates on ethics, philosophy of religion and selfhood. Kierkegaard develops an original argument according to which wholeheartedness requires both moral and religious commitment. In this book, Roe Fremstedal provides a compelling reconstruction of how Kierkegaard develops wholeheartedness in the context of his views on moral psychology, meta-ethics and the ethics of religious belief. He shows that Kierkegaard's influential account of despair, selfhood, ethics and religion belongs to a larger intellectual context in which German philosophers such as Kant and Fichte play crucial roles. Moreover, Fremstedal makes a solid case for the controversial claim that religion supports ethics, instead of contradicting it. His book offers a novel and comprehensive reading of Kierkegaard, drawing on important sources that are little known.