In conjunction with the 1993 International Conference on Logic Programming (ICLP'93), held in Budapest Hungary, two workshops were held concerning the implementations of logic programming systems: Practical Implementations and Sys- tems Experience in Logic Programming Systems, and Concurrent, Distributed, and Parallel Implementations of Logic Programming Systems. This collection presents 16 research papers in the area of the implementation of logic programming systems. The two workshops aimed to bring together sys- tems implementors for discussing real problems coming from their direct experience, therefore these papers have a special emphasis on practice rather than on theory. This book will be of immediate interest to practitioners who seek understanding of how to efficiently manage memory, generate fast code, perform sophisticated static analyses, and design high-performance runtime features. A major theme, throughout the papers, is how to effectively leverage host imple- mentation systems and technologies to implement target systems. Debray discusses implementing Janus in SICStus Prolog by exploiting the delay primitive, which is fur- ther expounded by Meier in his discussion of various ECRC systems implementations of delay primitives. Hausman discusses implementing Erlang in C, and Czajkowski and Zielinski discuss embedding Linda primitives in Strand. Denti et ai. discuss implementing object-oriented logic programs within SICStus Prolog, a theme also explored and compared to a WAM-based implementation by Bugliesi and Nardiello.