This present volume is the Proceedings of the 18th International C- ference on Nearrings and Near?elds held in Hamburg at the Universit¨ at derBundeswehrHamburgfromJuly27toAugust03,2003. ThisConf- ence was organized by Momme Johs Thomsen and Gerhard Saad from the Universit¨ at der Bundeswehr Hamburg and by Alexander Kreuzer, Hubert Kiechle and Wen-Ling Huang from the Universit¨ a ¨t Hamburg. It was already the second Conference on Nearrings and Near?elds in Hamburg after the Conference on Nearrings and Near?elds at the same venue from July 30 to August 06, 1995. TheConferencewasattendedby57mathematiciansandmanyacc- panying persons who represented 16 countries from all ?ve continents. The ?rst of these conferences took place 35 years earlier in 1968 at the Mathematische Forschungsinstitut Oberwolfach in the Black Forest inGermany. Thiswasalsothesiteofthesecond,third,?fthandeleventh conference in 1972, 1976, 1980 and 1989. The other twelve conferences held before the second Hamburg Conference took place in nine di?erent countries. For details about this and, moreover, for a general histo- cal overview of the development of the subject we refer to the article "On the beginnings and developments of near-ring theory" by Gerhard Betsch [3] in the proceedings of the 13th Conference in Fredericton, New Brunswick,Canada. Duringthelast?ftyyearsthetheoryofnearringsandrelatedalgebraic structures like near?elds, nearmodules, nearalgebras and seminearrings has developed into an extensive branch of algebra with its own features.