Why were the twin disk in wanted by Caroline b cooney so important?

In "The Face on the Milk Carton" by Caroline B. Cooney, the twin disks are important because they serve as a link to Janie's true identity and past. They provide clues about her mysterious disappearance as a child and help her piece together the truth about her origins. Janie's discovery of the disks ultimately leads to a reunion with her biological family.