“One of these days,” a friend said when my daughter was two months old, “you’ll wake up in the morning and realize you’ve slept through the night.” Half crazy with lack of sleep, I couldn’t even imagine it.

When the baby cried at night, I would get up, back aching, feel for my robe, and walk across the unswept floor to nurse her. I’d rock her a little. Then, in the quiet, I would hear a voice in my head whisper, Remember this. Pay attention. And I took it all in: the baby’s warm, trusting weight; her head in the bend of my arm; her little hand on my breast; her eyes shining up at me.