Kierkegaard ranks among history's greatest philosophers and ranks even higher among history's greatest Christian philosophers. While Kierkegaard has some writing that predates his conversion, even it is concerned with finding true religion and with the possibility of Christian conversion in particular. As a result, Kierkegaard's focus throughout his writing is on the nature of the Christian life, on the nature of human sin, and on how God in the form of Jesus Christ teaches men real Truth and how to become their true selves.