When I was researching These Fevered Days, I kept a “dailiness” file filled with particulars about Emily Dickinson’s world. Dickinson was a great doodler, for example, and excelled in catching mice. She loved ice cream and her mother’s fried donuts, and made fun of her sister’s snoring. The poet wrote on whatever was handy, including a flier advertising lavender cordials. I also saved details about Dickinson’s family: her father’s constant worry about wet feet, tumbling woodpiles, and aggressive cattle hooking his children; a description of the poet’s beloved Amherst evoking the town’s mixture of refinement and runty charm, “A village church with pillar’d front,” she wrote, “decked off in taste and elegance, except a little squat.”

I made note, too, of an incident involving Emily’s girlhood friend Helen Fiske, who, years later, would become the celebrated writer Helen Hunt Jackson. Helen jabbered so much at school she once had to sit for 20 minutes wearing a dunce cap with a corncob between her teeth. I liked the detail because it revealed Helen’s spunk, and offered a vivid warning to girls with much to say.