This volume contains the proceedings of the Fourth Workshopon Languages andCompilers for Parallel Computing, held inSanta Clara, California, in August1991. The purpose of theworkshop, held every year since 1988, is to bring togetherthe leading researchers on parallel programming languagedesignand compilation techniques for parallel computers. The papers in this book cover several important topicsincluding: (1) languages and structures to representprograms internally in the compiler, (2) techniques toanalyzeand manipulate sequential loops in order to generatea parallel version, (3)techniques to detect and extractfine-grain parallelism, (4) scheduling and memory-managementissues in automatically generated parallel programs, (5)parallel programming language designs, and (6) compilationof explicitly parallel programs. Together, the papers give a good overview of the researchprojects underway in 1991 in this field.