This publication is a record of the meeting of the International Institute for Applied Systems Analysis (IIASA) Task Force on Long-Term Economic Planning, held at Schloss Laxenburg in April 1978. It was natural that IIASA, having a collaborative East-West Basis, should sponsor a meeting that could promote an exchange of experience among centrally planned and market economies. Fourteen leading specialists were invited to present their ideas in a seminar-like setting; no formal papers were solicited. The result of these informal deliberations is presented here in the form of a progress report.