This volume contains 27 research articles on topics in universal algebra and its applications, lattice theory and cryptology. In continues the series "Contributions to General Algebra", Volumes 1-9, published from 1979 to 1995. All submitted manuscripts have been refereed by an international board. The papers were presented to the 54th Conference on General Algebra, May 29 to June 1, 1997, at the University of Klagenfurt, Austria. This meeting brought together 87 algebraists from 15 different countries.