The 142 papers selected for this scientific symposium, organized in conjunction with the 8th Icomos General Assembly Old Cultures in New Worlds, are published in these two volumes. They illustrate the variety of problems approached in the countries and the geographical regions represented. In themes one and two collected together in the first volume, the authors expose the different conceptions of conservation -- reflections on the theory and presentation of case studies -- and explain diverse techniques: aerial photography, pollutants measurement, nondestructive tests, inventories, as well as pedagogy and training in conservation. Themes three and four grouped together in the second volume, treat the relationship of heritage to its environment -- in particular, rural architecture -- and the management of monuments -- tourism, financing, legislation. A wide view is presented of the problems which have yet to be solved and also of the perspectives and possibilities offered due, in particular, to a more efficient technology, a greater public awareness, and the training of experts. -- AATA