This book constitutes the thoroughly refereed postproceedings of the 17th International Workshop on Algebraic Development Techniques, WADT 2004, held in Barcelona, Spain in March 2004.

The 14 revised full papers presented together with an invited paper were carefully selected during two rounds of reviewing and improvement. Among the topics addressed are formal methods for system development; specification languages and methods; systems and techniques for reasoning about specifications; specification development systems; methods and techniques for concurrent, distributed, and mobile systems; and algebraic and co-algebraic foundations.