John Duncan was born in Aberdeen in 1796. His father, a local shoemaker, was once described as 'upright...walking in the fear of God, strict in his Secession principles, rugged and strong, in family discipline inexorable'. Duncan's own spiritual pilgrimage was, however, tortuous and painful. His pathway to faith took him through unbelief and heresy, even although he had offered himself for the work of the Christian ministry. In retrospect his experiences prepared him for the quality of Christian service which later characterized his life and work, most notably as Professor of Hebrew in New College, Edinburgh. A man of brilliant intellect, Duncan is often only known today by the anecdotes which memorialise the eccentricities which marked hs life- as is often true of men of genius. But it is by his spiritual experience he is best remembered. It was deep and all-demanding, and not without its on-going struggles. But through it he came to a grace, understanding and wisdom possessed by few. For that reason alone contemporary Christians can learn much from these reminscences of his life.