A product of five years of ground-breaking research, What Tourism Managers Need to Know sets out a system for measuring the environmental health of destinations, so that tourism can be sustainable. Like a canary in a coal mine, environmental indicators are used as an early warning system to alert authorities of areas of concern so that action can be taken in time. This publication explains how to use 10 core environmental indicators and a series of site-specific indicators for tourism destinations in coastal zones, mountain regions, traditional communities, and small islands. It also discusses pilot testing of the indicators carried out in Canada, Mexico, Argentina, the Netherlands, and the USA.