Just like this:
“Thus, I will get to know this man through his friends and acquaintances,” she wrote in her first column for the paper. “I will try to discover who he is without ever meeting him, and I will try to produce a portrait of him over an undetermined length of time that will depend on the willingness of his friends to talk about him—and on the turns taken by the events.”
Keep a detailed account of your encounters. Wait until the owner of the book (or phone) dies, and then publish your account.