Kierkegaard wasn't really a philosopher in the academic sense, yet he produced what many people expect of philosophy. He didn't write about the world, he wrote about life, about how we live, and how we choose to live. His subject was the individual and his or her existence, the "existing being." In Kierkegaard's view, this purely subjective entity lay beyond the reach of reason, logic, philosophical systems, theology, or even "the pretenses of psychology." Nonetheless, it was the source of all these subjects. The branch of philosophy to which Kierkegaard gave birth has come to be known as existentialism, a much discussed and debated topic of philosophy.

In Kierkegaard in 90 Minutes, Paul Strathern offers a concise, expert account of Kierkegaard's life and ideas and explains their influence on man's struggle to understand his existence in the world.

The book also includes selections from Kierkegaard's work, a brief list of suggested readings for those who wish to delve deeper, and chronologies that place Kierkegaard within his own age and in the broader scheme of philosophy.