The present conference is the third in a series on this topic sponsored by the NCP. Drs. HcGhee, l1estecky, Genco and Bowen are to be commended for arranging this truly comprehensive program. We are fortunate that they have been able to assemble such a wealth of expertise. Program staff considers the advice of scientists such as yourselves essential to the success of its mission. Your presentations and discussions will focus on the crucial problems to be solved in exploiting the secretory immune system to combat dental caries. The published proceedings will bring these to the attention of the research community quickly and hopefully they will stimulate new investigators to bring their talents to these problems. This meeting will, to a large extent, determine the direction of research sponsored by the NCP. Finally, I would like to thank the members of the planning committee for their dedicated efforts over the past two years, which have culminated in this symposium. Our thanks are also due to each of you, in advance, for contributing so freely to the success of this meeting.