It is a great pleasure to present this collection of papers from LCR '98, the Fourth Workshop on Languages, Compilers, and Run-time Systems for Scalable Computers. The LCR workshop is a bi-annual gathering of computer scientists who develop software systems for parallel and distributed computers. LCR is held in alternating years with the ACM Symposium on Principles and Practice of Parallel Programming (PPoPP) and draws from the same community. This fourth meeting was held in cooperation with ACM SIGPLAN on the c- pus of Carnegie Mellon University, May 28{30, 1998. There were 60 registered...