Professor Leif Johansen''s contributions to economic science are well documented in his articles and essays for economic journals, symposium volumes and Festschrifts, all of which are to be published by North-Holland. When initiating the idea of this collection, Professor Dale W. Jorgenson also suggested a memorial volume by associates and others that would include papers devoted to research topics directly inspired by Leif Johansen. In the present volume this idea is realised. Three topics are covered: production theory, multisectoral growth models and planning. The papers presented here were either under work at the time of Leif Johansen''s death or prepared especially for this volume.