This publication is devoted to promote the Ecosystem Approaches to Human Health concept and to disseminate the main conclusions of three international consultations held in 1999 and 2000 and sponsored by multiple international agencies and regional institutions. In the first three chapters, the authors introduced complementary perspectives, discussing the main conceptual and methodological challenges that are essential to the Ecohealth paradigm. While the first two papers refer to global issues, the third paper is devoted to the use of the Ecohealth approach to promote a better understanding of the ecological and social patterns of communicable and tropical diseases.