When Mansfield offered Woolf ‘scrupulously truthful’ friendship – ‘the freedom of the city without any reserves at all’ – Woolf had already playfully described her as ‘utterly unscrupulous’. Attacking ‘the same job’ of creating a new postwar aesthetics, they shared ‘priceless talk’ about their ‘precious art’ even as their friendship foundered in distance, absence, ‘quicksands’ of insincerity, misunderstandings, secrets, silences – reserves of all sorts. This essay considers this competitive, irreplaceable literary friendship through the veil of Katherine’s secrets, things we see that Virginia evidently couldn’t, or could see only after Mansfield’s death: Mansfield’s 1919 letters about Night and Day; her ‘doubtful’ unsigned 1920 review of it, ‘A Tragic Comedienne’; her 1915 war story, ‘An Indiscreet Journey’, unpublished until after her death, and its resonances with Colette’s war journalism; the open secrets of her posthumously published Doves’ Nest and Journal, which flow into Woolf’s creation of The Waves. Whether Mansfield’s mercurial ‘we’ voices their ‘public of two’, her exclusive alliance with Murry against Bloomsbury, or their postwar generation’s ‘change of heart’, her work, talk, and thought participate in – and even inspire – that ‘thinking in common’ Woolf theorises in A Room of One’s Own and abstracts as ‘the life of anybody’ in The Waves.