This volume comprises ten papers presented as plenary lectures on the occasion of the Second World Congress of the International Society of Applied Psycholinguistics (ISAPL) at the University of Kassel, Germany, from July 27 - 31, 1987. The articles collected in this volume focus on the production, comprehension and acquisition of languages from various empirical and theoretical points of view. This volume is case-based in that it does not claim to cover the full range of present-day psycholinguistic enquiry. It attempts, though, to make a case out of a representational variety of psycholinguistic phenomena, which might provide a window on a unified theory of language production, comprehension and acquisition. From this perspective, this volume aims at the presentation and discussion of various cases which, through analogical reasoning, may serve to shed light on and to solve new cases.