Este nmero especial de Unasylva tiene dos objetivos principales. Pone a disposicin de nuestros lectores una seleccin de algunos de los trabajos presentados en el importante Cuarto perodo de sesiones del Comit de Desarrollo Forestal en los Trpicos, de la FAO y, de esta manera, pone de relieve la principal preocupacin de la Organizacin en materia forestal: cul es la mejor manera y la ms adecuada para el hombre de utilizar la formacin ecolgica menos conocida, es decir, los bosques tropicales hmedos.

This bulletin gives an overview of the ninth session of the working party on Soil Classification and Survey of the European Commission on Agriculture that took place in Ghent, Belgium, in september 1973. It presents the papers, discussions and recommendations developed during the meeting. A methodology of land evaluation is being developed in FAO and will be used for the interpretation of the FAO/UNESCO Soil Map of the World with a view to making a global evaluation of the land resources available for agricultural development.

This special issue of Unasylva has two main objectives. It brings to our readers an edited selection of some of the position papers of the important 4th Session of the FAO Committee on Forestry Development in the Tropics and, in doing, this, it emphasizes FAO's principal concern in the field of forestry: how to make the best and wisest use of man's least understood ecological formation, the moist tropical forest.