From hospital stays to Shabbat dinners, a few lines a day became a Jewish way of reckoning with memory, loss — and the comfort of routine. In January 2011, I wrote my first entry in a five-year diary.

A diary can construct a false narrative, but the abstract snippets of a notebook let reality come into focus. By Daniel Poppick “Hello, I’ve never met you before, so it really is a pleasure. I hope ...