Minimalism assumes that language consists of a lexicon and a computational system, with the latter embedded in two performance systems: articulatory-perceptual and conceptual-intentional. Two linguistic levels, phonetic form (PF) and logical form (LF), interface with the performance systems. A computation converges at the interface levels if it contains only legitimate PF and LF objects. However, we cannot define linguistic expressions simply as PF/LF pairs formed by a convergent derivation and satisfying interface conditions. The operations of the computational system which produce linguistic expressions must be optimal, in the sense that they must satisfy some general considerations of simplicity, often referred to as Economy Principles. One of them, the Last Resort Condition (LR), prohibits superfluous steps in a derivation. It requires that every operation apply for a reason. It has often been argued that a similar condition constrains representations, prohibiting superfluous symbols. These conditions require that derivations and representations in some sense be minimal. This article discusses the working of LR, as it applies to both derivations and representations. It starts with the former, examining how LR applies to both Move and Agree. © editorial matter and organization Cedric Boeckx 2011.