Since much of the rhetoric around recent outbreaks of the measles revolves around concern for the well-being of children, perhaps the strongest advocate to answer our concerns is a beloved author of children’s literature. The Guardian shares an emotional letter from Roald Dahl, who lost his seven-year-old daughter Olivia to the disease at a time when vaccination rates in England were still low enough to preclude herd immunity. Dahl tells the story of his daughter’s rapid decline and urges parents in no uncertain terms to take the simple step to avoid reliving his tragedy.