This volume contains papers presented at the second International Workshop on Word Equations and Related Topics (IWWERT '91), held at the University ofRouen in October 1991. The papers are on the following topics: general solution of word equations, conjugacy in free inverse monoids, general A- and AX-unification via optimized combination procedures, wordequations with two variables, a conjecture about conjugacy in free groups, acase of termination for associative unification, theorem proving by combinatorial optimization, solving string equations with constant restriction, LOP (toward a new implementation of Makanin's algorithm), word unification and transformation of generalizedequations, unification in the combination of disjoint theories, on the subsets of rank two in a free monoid (a fast decision algorithm), and a solution of the complement problem in associative-commutative theories.