Not quite a memoir, not quite a collection of essays, Maggie O’Farrell’s I Am, I Am, I Am is a group of personal narratives recounting the times when her life edged dangerously close to death. The subtitle, “Seventeen Brushes with Death,” is powerful in itself, but even more so when you read what she experienced. Each chapter begins with an illustration of a symbolic body part and the year of its occurrence. In “Neck,” O’Farrell, on a solo hike in 1990, fends off a man she chances upon in the