Themes of existential crisis found in the autobiographical works of philosopher Søren Kierkegaard include the exploration of anxiety, despair, and the search for meaning in life. Kierkegaard's reflections reveal the struggles individuals face when confronting their own existence and the often conflicting demands of society and personal beliefs. His writings delve into concepts like the "leap of faith," emphasizing the importance of personal choice and individual responsibility amid the chaos of life, thus laying the foundation for modern existential thought.