The International Congress on Rapid Methods and Automation in Microbiology and Immunology, held in 1990 (RAMI-90) in Helsinki Espoo, Finland, attracted considerable interest from the international scientific community. This reflects both the rapid progress and numerous new challenges in the field covered by RAMI-90. New biotechnical approaches, such as the polymerase chain reaction, recombinant gene products and synthetic peptides are gaining wide acceptance. New important pathogens have emerged, such as hepatitis C, Helicobacter pylori, Borrelia burgdorferi, herpes virus 6 and Chlamydia pneumoniae. "Super streptococci" are recognized again as well as the agent responsible for bovine spongiform enceph alopathy. The current diagnostic methods are clearly unsatisfactory for many of these and other microbes. Moreover, there is an increas ing need for more accurate microbial control of our environment, and of the food and water we consume. What is needed are rapid, sensitive and reliable procedures which, on the one hand, should be suitable for automation and, on the other hand, presented in a cost-effective version suitable for field use. We view these needs as a clear and loud challenge for future RAMI congresses. This volume provides an up-to-date presentation of the highlights of RAMI-90 and prospects for the future. For the preparation of this volume we wish to thank Dr. Maija Leinonen for her invaluable con sultation and Ms. Virpi Tiilikainen for secretarial assistance. ANTTI V AHERI RICHARD C. TILTON ALBERT BALOWS Contents Nucleic Acid Detection Controlled Synthetic Oligonucleotide Networks for the Detection of Pathogenic Organisms M. S. Urdea . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ."