ICTP's Fifth Course on Mathematical Ecology will be held from 28 February to 24 March. The first three weeks of the Course will explore such topics as the ecology of populations and communities, food webs, ecosystem assessments, epidemiology and global ecology. In addition, and for the first time, a fourth week will examine ecological economics discussing market failures to deal with the environment while introducing such new ideas as valuations of "ecosystem services" and how to use this approach to promote sustainable development. Reflecting on the Course's multidisciplinary nature, participants will include mathematicians, economists, biologists, and environmental engineers.