This Festschrift volume, published in honor of Kokichi Futatsugi, contains 31 invited contributions from internationally leading researchers in formal methods and software engineering. Prof. Futatsugi is one of the founding fathers of the field of algebraic specification and verification and is a leading researcher in formal methods and software engineering. He has pioneered and advanced novel algebraic methods and languages supporting them such as OBJ and CafeOBJ and has worked tirelessly over the years to bring such methods and tools in contact with software engineering practice. This volume contains contributions from internationally leading researchers in formal methods and software engineering.