The 5th Pathogenic Neisseriae Conference was held in Noordwijkerhout, The Netherlands, on 15-18 September 1986. It followed San Francisco - USA (1978), Hemavan - Sweden (1980), Montreal - Canada (1982), Asilomar - USA (1984). These conferences will continue to be held in the foreseeing future. The reason for this is because studying pathogenic Neisseriae enables research workers to look at many aspects of bacterial infectious diseases. These aspects include: - Epidemiology and vaccination (section 1) - Genetic aspects of antigenic diversity (section 2) - Outer membrane proteins and...