The main content of this book is concerned with an epidemiological study of lung can-cer, which was conducted in Pingliang and Qingyang Prefectures of Gansu Province, Chinaduring 1994 - 1998. This is a joint project of Laboratory of Industrial Hygiene, Ministry ofHealth, China and National Cancer Institute, National Institute of Health, USA. Good co-operation between Chinese and American scientists and their hard works made the programsuccessful. Results from the epidemiological study will be great contributor to etiology oflung cancer. There are many environmental factors, which could cause lung cancer, such assmoking, arsenic, asbestos, particle, chloromethyl ethers, radon progeny and other agents.Especially the radon and its progeny are omnipresent in dwellings, schools, working placeand everywhere. Although the fact, that exposure of radon and its daughters is one of thecauses of lung cancer, has been identified in mine environment, but little is known about ef-fect of indoor radon level from epidemiological point of view. The Gansu lung cancer studyfills in the gaps in area of effects of indoor radon exposure.

Papers from Gansu lung cancer study collected in the book concern with some aspects oflung cancer etiology: indoor radon, smoking, cooking oil, particles from coal and biomasscombustion, previous pulmonary diseases, reproductive factors and others. The book wouldbe helpful in progress of setting national standards of indoor air pollution. It also collectssome papers from other studies concerning lung cancer, radiation effects, natural radiationand so on. These papers reflect research activities in each field in China.

Gansu lung cancer study got a lot of assistance from local Government, especially fromHealth Department of Gansu Province, Health Department of Pingliang and Qingyang Pre-fectures, Health Bureau of each county (city) as well as from local investigators. All of themmake important contribution to the joint study. It is our pleasure to recommend the book toyou. Hope it will be useful.