The papers and reviews in the present volume are in part regular contributions submitted for publication in Biological Trace Element Research, and in part invited papers from participants of the International Symposium "Present Status and Perspectives of Sele- nium in Biology and Medicine," held on May 2 and 3, 1987, at the Eu- ropean Academy, Nonnweiler /Trier, FRG. The Symposium focused on ecological and biomedical aspects of selenium with emphasis on the manifestations of selenium deficiency in different countries, the distribution of selenium in human organs and body fliuds, the roles of selenium in health and disease, its anti carcinogenic action, effects of supplementation, and therapeutic applications. Organized jointly by the International Association of Bioinor- ganic Scientists and BioSynopsia, a Nonprofit Subsidiary of the Tech- nology Center, Stuttgart, the scientific board consisted of Professors W. Hartfiel, Bonn, FRG, G. N. Schrauzer, La Jolla, CA, USA, and H. Zumkley, Muenster, FRG.