This article presents and analyses a set of notes written by the psychoanalyst Melanie Klein following an operation in 1937. The notes, entitled Observations after an Operation, act as a case study of the intersection of psychical, material and social relations as they play out in the immediate aftermath of surgical intervention. Using a close reading method, the article contextualises an analysis of Observations after an Operation by linking it to Klein's wider corpus of theoretical work. It deals in turn with the representation of anxiety mechanisms in the patient experience, drawing upon Klein's notes on the similarity with 'anxiety-situations' in early childhood; with Klein's changed relation with both external objects and their counterparts in the individual's mental landscape; with the role of sensation in phantasy, and the connection to bodily pain; with the doctor-patient relationship and the way this is perceived as being embodied in material objects, played out across two dreams experienced by Klein during her recovery; with the emphasis on illness as a form of mourning; and with the creative potential that the experience offers for a renewed structure of object relations. The article concludes that a greater attention to the role and representation of material objects, using psychoanalytic object relations theory as a starting point, can enhance how we collectively understand and assess the psychical impact of healthcare settings upon the patient. It also invites other scholars across the critical medical humanities to consult and analyse the newly available text upon which this article is based.