The Danish philosopher and religious thinker Søren Aabye Kierkegaard (1813-1855) was the progenitor of 20th-century existential philosophy.

Søren Kierkegaard was born in Copenhagen on May 5, 1813. His father, Michael Pedersen Kierkegaard, was a self-made man who had amassed a considerable fortune as a wool merchant. At the age of 40 he retired and devoted himself exclusively to the intellectual life. His house became a meeting place for university professors, prominent clergymen, and writers of the day. Søren, the youngest of seven children, had a slight physical handicap. He was sickly, and frail, yet highly gifted, and his father's favorite. He was brought up in a house where discussion and debate were as familiar as the furniture.

At the time of Søren's birth Michael Kierkegaard was 57, a highly respected and rather formidable patriarch who attempted to instill an austere and demanding Christianity into...