It was, let me acknowledge, an old-school response. A major life cycle event was underway — becoming a grandmother or, to use the Yiddish name I’ve chosen, becoming Bubbe. So I began looking for a helpful book. Others might prefer a website like The Grandparent Effect, where the writer Olivia Gentile passes along news, interviews and studies. But I wanted a book I could underline and dog-ear and stick Post-its on. I had in mind an authoritative user’s manual, a later-life counterpart to the Penelope Leach baby and child guide I’d relied on as a parent.