this book constitutes the refereed proceedings of the 9th international conference on rewriting techniques and applications, rta-98, held in tsukuba, japan, in march/april 1998. the 22 revised full papers presented were carefully selected from a total of 61 submissions by the program committee with the assistance of 113 additional referees. the book covers all current aspects of rewriting including rewriting systems, term rewriting, string rewriting, theorem proving, resolution, normalization, unification, equational logics, lambda calculus, constraint solving, and functional programming.