Imagine buying a vintage Hermès address book on eBay and then realizing it belonged to Dora Maar, the artist and poet who is best known for having been Picasso’s mistress and muse! Brigitte Benkemoun, the author of Finding Dora Maar, describes her process of deducing the address book’s origins:

A-B: The first entry is illegible because it is partly blotted out with black ink. The second might be ANDRADE, then AYALA. On the fourth line is the first familiar name: ARAGON! Followed by a few contacts that call up nothing for me: ACHILLE de MÉNERBES, BERNIER, BAGLUM . . . Then a few entries for whom he or she listed an address as well, perhaps because they were closer friends: BRETON, 44, rue Fontaine; BRASSAÏ, 81, rue Saint-Jacques; BALTHUS, château de Chassy, Blismes, Nièvre.

For the letter C, COCTEAU is the first entry: 36, rue de Montpensier, RIC 5572, or 28 in Milly. But are the first entries always the closest friends? And this poet was such a figure on the Paris social scene that everyone must have known his number. Followed by the painters COUTAUD, 26, rue des Plantes; CHAGALL, 22, place Dauphine . . .

After going through the address book, recognizing many famous names and deciphering other details, she realizes that there’s only one person who could have owned it:

Of course, it must be her! Everything fit, it all matched, up to Picasso’s absence at the letter P. In 1951, six years after their breakup, she did not copy his address or his phone number into her new address book, not being able to erase him in any other way. Maybe this wasn’t “a Picasso.” But it was the address book of Dora Maar that I held in my hand!

Such a cool story, and such a gorgeous little address book!

Read more: A Vintage Address Book Bought on eBay Listed the Addresses of Dozens of Art Historical Legends. It Turned Out to Be Dora Maar’s