In 1992 the Centre of Environmental Science (CML) at Leiden University, The Netherlands, published a Guide on Environmental Life Cycle Assessment (LCA) methodology. Many copies of this guide have been sold all over the world, setting the standard for a long time.Since then LCA methodology has progressed enormously and the International Organization for Standardization (ISO) has published a series of Standards on LCA. These developments have now been incorporated into a new Handbook on LCA authored by CML in cooperation with a number of other important institutes in the area of LCA. The general aim of this Handbook on LCA is to provide a stepwise `cookbook' with operational guidelines for conducting an LCA study step-by-step, justified by a scientific background document, based on the ISO Standards for LCA. The different ISO elements and requirements are made operational to the `best available practice' for each step. This book will appeal to persons from a wide range of scientific disciplines working in industry, in government, as consultants, or at university, who are interested in learning more about LCA and in performing LCA studies. It will be of especial interest to students and researchers in the field of LCA, industrial ecology, and those interested in environmental sciences in general. CML is strongly involved in the development of a standard methodology to determine environmental impacts of products, i.e., LCA. This is done within international fora such as the Society for Environmental Toxicology and Chemistry (SETAC), the International Organization for Standardization (ISO), and the United Nations Environmental Programme (UNEP).