Book excerpt: These Proceedings of a NATO-ARW (HTECH ARW 97 1843) held at the Oreanda Hotel, Yalta, Ukraine from April 29 till May 2 , 1998 resulted from many discussions between various workers, concerning the need for a gathering of all (if possible) who were concerned with the subject of symmetry of the order parameter and pairing states for superconductivity. We applied ourselves in particular to High critical Temperature Superconductors (HTS), but also studied other unconventional superconductors. The study of HTS is one of the most prominent research subjects in solid state sciences. The understanding of the role of symmetry and pairing conditions are also thought to be necessary before technological applications since these features may be influenced by external fields. The workshop discussions have touched upon theoretical and experimental aspects, but also on related topics. These served as initiators for a very great amount of discussions with many comments from the audience. More than thirty "long lectures" and one on going "poster session" were held. Private discussions went unrecorded but obviously took place at many locations : lecture halls, staircases, cafes, bedrooms, bars, beach,bus, plane... Arguments openly reported for the first time were often quite sharp ones, -and this is an understatement.