The 2019 first edition of The Yellow Paper noted an intergenerational intention to ‘clear the air’. The metaphorical air Norman Denny refers to in his introduction to the collected edition of The Yellow Book, published in 1950, relates to the outrage fuelled by the original quarterly volume (1894-1897). In 1969, the year Denny writes of ‘dusting down’, of the need to question and overturn the status quo, philosopher Ludwig Wittgenstein is scoring 676 aphorisms, published as On Certainty (Über Gewissheit), which starkly reminds us that uncertainty is an intimate, everyday matter. The air of 2021, with its bindle of sickness, continues to highlight the ineffable ‘groundlessness’ to different and various ways of being-in-the-world and the related contextual and contingent qualities we take for granted. Of certainty. There is a personal dimension to the experience of not knowing exactly what our world is and where we, and our world, are heading.