But haven't historians already learned that she was del Giocondo? Isn't it part of one of the other names of the famous portrait? I even remember playing an old Mario Bros. history game that mentioned this (that's probably how I remembered, hahaha.)

This kind of book is new, but her name is not.

This is totally a new thing saan-kpa. Historians knew her "marriage name", and as the wife of Francesco del Giacondo. Her real name, her identity before the marriage, her birthplace and her family was a secret. This is why many scholars thought Mona Lisa could be a "composite" character which Da Vinci created with the inspiration of del Giacondo's wife. Now, if this historian is right, we know who really she was, where she was born and lived, along with some details about her family.