Last spring, I celebrated the twenty-fifth anniversary of the greatest turning point in my life. In April 1970, at the age of twenty-three, I found myself climbing the western slope of the Mount of Olives, facing Jerusalem and the Dome of the Rock. By midafternoon I had returned to the foot of the mountain and entered the Garden of Gethsemane, a lush patch of green adjoining a Russian Orthodox church and filled with roses and olive trees. The ancient trees inspired within me a deep sense of awe surpassing any I’d ever felt, though comparable to my childhood response to the blowing of the shofar that signaled the close of Yom Kippur each year.

Mark O’Brien spends virtually every moment of every day encased in an iron lung in a room eleven feet wide and twenty feet long and seven and a half feet high. A single window fronts an alley and gets little light. The air in the room has a damp weight and smells sour, like the laden air of a closed space in which people have slept. Certain sounds are constant: the graduated chant and metallic rattle of the iron lung’s small electric motor; the regulated hiss of its leather bellows; the crumpling of a nylon collar around Mark’s neck as air from the lung fills and leaves it; and the soft intermittent clatter in Mark’s mouth and nose and throat: sighs, gasps, wheezes, whistles.

It was my first office, a narrow dormer room with barely enough space for a desk and a chair.