This paper inquires into the inability of subjects in English to topicalise. Treating topicalisation as a specific case of d-linking, it asks: why don’t subjects topicalise in English? And why cannot they be d-linked through further movement? It concludes that the property of [aboutness] of subjects is anunder specified instance of a more composite derivative effect realised as [topic]. Given the ability of objects in English to be readily d-linked through extraction in CP, the analysis takes a detailed look at the structural differences between subjects and objects. It concludes that d-linking of an argument is contingent upon the derivational memory of its prior inclusion within vP that has yielded its denotational set-membership. Treating EPPas an A’-operation that embeds one instance of the subject-chain into discourse, the inability of subjects to topicalise is explained as an “on line” denotational dependency on discourse, which lacks the systemic memory of the subject’s embedding. In turn, their immobility is treated as a modular dependency between the two subject copies, mediated through Texcluding the one instance of the chain.