This book summarizes work done by the authors under the Esprit Tool Use project (1985-1990), at GMD in Karlsruhe and at Berlin University of Technology. It provides a comprehensive description of the generic development language Deva designed by the authors. Much of the research reported in this monograph is inspired by the work of Michel Sintzoff on formal program development; he contributed an enlightening Foreword. Deva is essentially a typed functional...