This volume contains the background texts for an IFIPState-of-the-Art Seminar on Formal Program Development, heldin early 1992 near Rio de Janeiro, Brazil.The book stems from work done by IFIP Working Group 2.1 onAlgorithmic Languages and Calculi. Since 1975, the WorkingGroup has increasingly focused on systematic approaches toprogramming and on appropriate concepts and notations tosupport such approaches. Today, the calculation of programsfrom specifications constitutes the central theme ofthegroup's work. Thus the core interests of the group are:- formal specification of solutions to problems, and- formal development/calculationof programs from suchspecifications.