Industrial impact on the environment tends to be defined in "end-of-pipe" terms such as pollution and waste. This report examines the extent to which natural resources are used to fuel industrial economies, and reveals that nearly four-fifths of these vital "inputs" are hidden: they do not enter the economy and so are not measured directly, yet the environmental impacts are significant. It also shows that much of the natural resources needed to sustain an industrialized economy occur outside that country's borders. Case studies include the United States, Germany, Japan and The Netherlands.