This book provides an introduction to the dynamic subject of corporate environmental accounting. It outlines the business case and rationale for engaging in environmental accounting. It also illustrates how leading UK companies are already adding value and reducing risk through the use of innovative environmental accounting techniques and methodologies. The second part of the book presents an environmental accounting tool kit which focuses on external cost accounting. The methodology detailed in this section provides a tool to estimate the environmental sustainability of a company's activities and operations. The methodology presented has been developed by the sustainable development organisation Forum for the Future, a UK registered charity, with support from the Chartered Institute of Management Accountants (CIMA). It is an introductory guide to environmental accounting. It will help organisations identify and cost their impact on the environment.