International Rhinologic Society Rhinology 0300-0729 2026 10 17 Letters in Rhinology EN S. Reitsma AmsterdamUMC, Amsterdam, the Netherlands Editorial 3644 10.4193/Rhin26.906 Recently, it struck me how our societies are increasingly occupied with (automated) written texts. It means words still matter, and so do their building blocks: letters. For this issue of Rhinology, I think the letter ‘o’ could be put as central denominator. You might wonder: “Y?”. Well, first of all because the ‘o’ stands for ‘olfaction’. In this issue we present some wonderful studies regarding olfaction, the loss of it, how to determine it, its impact, and its recovery or its replacement. Next, the ‘o’ is for ‘obstruction’ and how it might impact sleep quality.