Abstract.  We observe that superlative noun phrases are often not definite and may be headed by an indefinite determiner and other determiners. We attribute this fact to the semantics of the superlative morpheme which creates a (not necessarily singleton) set of individuals. A welcome prediction made by this proposal is that negative polarity items (NPIs) are licensed in the postnominal position only when the determiner that precedes the superlative morpheme is definite, because only then does the superlative morpheme have the semantic property required for NPI licensing—namely, Strawson Downward Entailingness. We explore some semantic and syntactic consequences of the proposal.