Human adults experience the disease we call "the common cold" an average of 2 to 4 times a year. What do scientists know about the so-called "common cold", and why haven't we figured out a way to end this illness? This long-form essay from The Guardian's Nicola Davison, published on October 6, 2017, investigates the history of research into the cold (and some of the unsuccessful ways that people have tried treat it) and outlines what scientists currently understand about the disease and how it spreads. Topics covered in this essay include the UK's Common Cold Unit (CCU), an organization that conducted research on the common cold between 1946 and 1990; the current research of Sebastian Johnson of the School of Medicine in the Imperial College's Saint Mary's Hospital; and the ongoing research of Emory University pediatrician Martin Moore. This essay, like all long reads by The Guardian, is also accompanied by an audio version that may appeal to podcast fans.