The papers contained in this volume were presented at theFourth Annual Symposium on Combinatorial Pattern Matching,held in Padova, Italy, in June 1993.Combinatorial pattern matching addresses issues of searchingand matching of strings and more complicated patterns suchas trees, regular expressions, extended expressions, etc.The goal is to derive nontrivial combinatorial propertiesfor such structures and then to exploit these properties inorder to achieve superior performance for the correspondingcomputational problems. In recent years, a steady flow ofhigh-quality scientific studies of this subject has changeda sparse set of isolated results into a full-fledged area ofalgorithmics.The area is expected to grow even further due to theincreasing demand for speedand efficiency that comesespecially from molecular biology and the Genome project,but also from other diverse areas such as informationretrieval, pattern recognition, compilers, data compression,and program analysis.