Computers not only extend our capability for handling large amounts of data and perform sophisticated processes, they also extend our capabilities for making better decisions and exploring widely and deeply different alternatives that otherwise could only be mentioned in passing. Computers have had a great impact in all kinds of human activities, yet for the most part architects were, and some are still reluctant to their application in this field. It is argued that computers can not solve architectural problems, owing to the great subjectiveness involved, or that they tend to obliterate creativity. It is intended here to demonstrate, in the first case, that the computer is not used to "solve" the problem but to help to analyze and make better decisions in a more rational and systematic way and, in the second case that this help will broaden architect's creativity by helping him respond realistically to the problems and by increasing his means to test the validity of his solutions. It is assumed that it is still, and will always be, up to the architect to be creative using computers, and not the reverse. It is only through a systematic approach that problems will be stated properly and that solutions can be expected to approach or reach optimality. Intuition, experience and creativity must be present throughout the whole process of architecture, complementing rather than supplementing rational decisions. Computers do not provide merely numbers, but most importantly the means for evaluating the consequences of making decisions, before they are implemented. Part I of this work is a brief introduction to the ideas leading to the author's arguments, and exposes in detail two cases studied, one for data processing and one for problem solving. Documents complementing this discussion are presented for reference as appendices. Part II deals with some references about experiences already obtained in operations research work, continuing with part III which deals with the relevance of computers in the architectural process, and the importance of interfacing devices (Input/Output). Part IV is a brief summary and statement of conclusions and finally part V presents appendices and a bibliography.