Faced with the deteriorating biodiversity of species and the mounting threats to the planet's ecosystems, Senators Pierre Laffitte and Claude Saunier endeavoured to determine: - the procedures and means which would allow for a better understanding of this biodiversity; - the possibilities to improve its protection; - the necessary conditions for its sustained development. Their study complements that already presented on climate change and the energy crisis, and is meant to establish the basis for what could become the model of economic development for the next half century.