Addressing current generative concerns over the Left Periphery of clause structure, this paper proposes a categorial distinction, based on the choice of value for the feature [±FINITE], between two functional heads, C° and Top°, which project into CP and TopP, respectively. The choice is responsible for a principled distinction between structural (TopP) and rhetorical (CP) topicalization. Primary data are Det-clefts, Hv-clefts and so-called sikke-expressions in Danish. The latter are peripheral to the core of Danish grammar, but are nevertheless – or perhaps therefore – a mine of evidence for the distinction argued for. Criterial evidence is a conjunction of three diagnostics: lack of V2 word order, so-called ‘pleonastic’ complementizers and the syntactic behaviour of expletive der. It is argued that normal (left) movement principles cannot account for the sharing of information between the Specifier and the Complement of Top°. Instead, two possibilities for interpretation are tentatively explored, involving various kinds of Right Periphery phenomena. Since the Specifier and the Complement of Top° each provides the structural basis for independent, clause-like utterances, TopPs are seen as clear cases of BREAKSTRUCTURES.