This paper discusses the genitive of negation in Russian, one of the most well-studied case alternations that exists in the language and the most well-known diagnostic for unaccusativity. Direct objects and subjects of unaccusative predicates may occur in the genitive case under sentential negation, alternating with accusative and nominative, respectively. When these Noun Phrases (NPs) appear in the genitive, they tend to receive an indefinite, non-specific, or existential interpretation. Recent semantic analyses of this construction argue that such NPs are best treated as properties of type <e,t>, which are the result of a type-shifting operation. In this paper, we examine five different types of approaches in analyzing this construction and show that in spite of the range of proposals that exists, a number of issues remain. The genitive of negation presents a puzzle that lies at the heart of the syntax–semantics interface. Putting together the syntactic and semantic generalizations that have been noted for this construction in a coherent way can shed light on the overall architecture of the grammar.