The six essays in this volume discuss philosophical thought on scientific theory including:a call for a realist, rather than instrumentalist interpretation of science; a critique of one of the core ideas of positivism concerning the relation between observational and theoretical languages; using aerodynamics to discuss the representational aspect of scientific theories and their isomorphic qualities; the relationship between the reliability of common sense and the authenticity of the world view of science; removing long-held ambiguities on the theory of inductive logic; and the relationship between the actuality of conceptual revolutions in the history of science and traditional philosophical pictures of scientific theory-building.