Mom left no public record aside from a letter to the editor published in The Tulsa World. Instead, she had a dusty purple plastic bin she labeled “Memorabilia” with a Magic Marker. Inside were a prom program, a love letter from a boyfriend we had never heard of and hundreds of drawings, photos and notes from her grandchildren or us sisters as children. She had the photo albums she had made when we were little. A safe deposit box held her citizenship papers and other legal documents.

Nearly anything from the past 20 years existed only online, locked away behind passwords and firewalls. Notwithstanding the cards she made by gluing New Yorker cartoons onto cardstock, her written communications essentially stopped in the early 2000s, when she got an email account. She was a great texter, pouncing to be the first to respond in any group and embracing emojis with the passion of a preteenager. Her social media posts were politically passionate and at times head-scratchingly random.

I valued these public things, of course, but I also wanted more. We document our lives in two ways, one intended and one not. There are the emails we send, the photos we post and the comments we debate and wordsmith before hitting Return. And then there is the inadvertent record: the enraged first drafts, the unflattering selfies, the record of purchases at Amazon or Netflix, the digital sticky notes we had not meant to keep.

We work hard to curate the public self and rarely think about the shadow self. I knew from my own work, however, that off-the-cuff notes, old receipts, call logs and calendar entries can serve as proxies for feelings. A run of doctor’s appointments, a glut of calls to the same phone number that never picks up, the purchase of five types of acne cream or a self-help book — these are clues. When we are alive and artificial intelligence assembles these clues to hazard an eerily accurate prediction about our interests and future desires, we are horrified. But for a historian looking at the life of someone who has died, the same clues can lead to understanding.

As a daughter, my heart broke at the realization that digital records, along with the stories from those of us who loved Mom, were going to be the best way to be with her again, to learn from her again or to laugh again at her stupid jokes. But as a historian, my mind raced. If the only way to preserve her memories was to put together the pieces of her digital life, then we had to hack into her online accounts.

After a frantic hunt, my middle sister found a small pocket calendar in Mom’s desk. The back pages were filled with handwritten login IDs and passwords. I patted myself on the back for having insisted Mom record her passwords, and we sisters rejoiced … for about five minutes. At site after site, login page after login page, every attempt failed.

The only login and password combination that worked was for her Apple iCloud account, but she had protected it with two-factor authentication. We could see that her phone was receiving texts — texts from Apple containing the codes needed to get into her account — but we couldn’t unlock the phone, so we couldn’t see the code. I called a few high-powered techies I know from working at Stanford and living in Silicon Valley, but none of them could help. It seemed we would be locked out of everything.