Today companies face various different problems on software technologies. Difficulties of system design, of programs maintenance, of the co-operation to non-experts are examples of substantial problems that produce heavy economic losses. In this study, the author develops a mathematical framework and puts under a new light the analysis and programming methodologies. These are not given as facts but are inferred, they are discussed and are critically evaluated. The reader's mind is solicited to reason out the everyday problems. The first part of the book provides the theoretical and cultural contexts, while the second part clarifies the software technologies. The book is centred on the structured methods and makes mention even of the object and visual technologies.