Summary This paper aescriDes a program, called "PRUW", which writes programs. PROW accepts the specification of the program in the language of predicate calculus, decides the algorithm for the program and then produces a LISP program which is an implementation of the algorithm. Since the construction of the algorithm is obtained by formal theorem-proving techniques, the programs that PROW writes are free from logical errors and do not have to be debugged. The user of PROW can make PROW write programs in languages other than LISP by modifying the part of PROW that translates an algorithm to a LISP program. Thus PROW can be modified to write programs in any language.