The 9th International Conference on Lymphatic Tissues and Germinal Centres in Immune Reactions was held in Oslo, 9-14 August, 1987. These conferen- ces, by the regular devotees just referred to as the germinal centre con- ferences or GCC, have been held regularly at roughly three-year intervals since 1966. The credo of these conferences is "in vivo veritas," signifying that investigating components, like molecules and cells, only gives partial truth. The components must ultimately be explored in their natural con- text, to see how they interact with other parts and are integrated to a whole....