The International Symposium on the Immunoglobulin A System was organized in observance of the twenty-fifth anni­ versary of the School of Dentistry of the University of Ala­ bama in Birmingham. Immunoglobulin A was chosen as the sub­ ject of the Symposium because of its broad scope in relation to all biologic sciences, as well as for its particular rele­ vance to prevention of the most common human disease—dental caries. More than 500 scientists, from 13 countries, met in Birmingham, Alabama to review critically past and current research on IgA and to outline goals for integrating future investigations of the many facets of the IgA system. It is our pleasure to express sincere appreciation to the following, whose efforts made the Symposium possible: to Dr. Sidney B. Finn, Chairman, and all members of the Twenty­ fifth Anniversary Planning Committee for their advice and assistance; to Dr. Charles A. McCallum, Dean of the School of Dentistry, for his enthusiastic approval and support; to Dr. Frederick W. Kraus, Symposium Chairman, for the countless hours of meticulous planning that ensured the smooth execution of the Symposium; to Ms. Tonnia C. Maddox whose unstinting dedication was indispensable to the organizational success of the meeting; to those who assisted with the transcription of manuscripts and discussions: Ms. Shirley Snow, Ms. Jan Allen, Ms. Janice Buchanan, Ms. Joy Fisher, Ms. Pam Honeycutt, Ms. Mary Huckabee, Ms. Charlotte Hughes, Mr. Stephen Miles, Ms.