Soren Kierkegaard’s reception as “the father of existentialism” tends to overshadow his contribution to Christian spiritual literature. However, it could be argued that Kierkegaard’s authorship aims to facilitate an inward deepening of the Christian, as found in the Christian mystics and Pietists preceding him. Christopher Barnett’s work serves as a thorough, well-argued, and yet remarkably readable introduction to the historical situation of nineteenth-century Danish Pietism, and consequently highlights the Christian spirituality behind Kierkegaard’s writing. Early on, Barnett pays special attention to the mystical influences on Johann Arndt’s thought, which will become important as he later argues that Kierkegaard adopts and refashions the German mystical tradition. Barnett recounts the Kierkegaard family’s relationship to the Moravians, the Brodresocietet, and the Grundtvigians, and Kierkegaard’s own engagement with Pietist literature, especially focusing on the imitatio Christi motif. Barnett’s historical analysis is rigorous without being exhaustive, informing the reader without overwhelming her.