Modern engineering systems are very complex and must be designed to meet conflicting constraints. The major hurdle facing an engineering designer is to find a way to meet these many competeing contraints in an affordable amount of time at an affordable price. Much work has gone on in computer science on the analysis of systems by formal methods. The hope of these technques is that the entire operation and requirements of a system can be captured in a mathematical model which would allow the 'correctness' of the sytem to its requirements to be proved.This is the major ideas of such distingushed researchers as Hoare and Parnas. Unfortunately these methods have never been found to work in practice. For anything but a toy system the complexity of the formal model becomes intractable. But there is a more important reason for the failure. How can 'correctness' be defined fro a real world system which must work in a filed of changing requirements.Gelernter identifies this problem but notes that it is solved everyday by real world engineers who must face real world requirements. These engineers are not deterred by the failure of formal methods. Instead they rely on a sense of beauty which is a sense gained from experience in how a system can meet its requiremtns. It is this abilty to see though the complexity to see the structure and pattern in the design that will dictate its degree of success that enable a human designer to function where strictly mathematical and logical techniques fail. Only techniques which use holistic thinking can succeed in in the real world.It is often thought that human reaoning pales beside the clarity of logic and mathematics in understanding the world and how devices function. Gelernter rightly points out that this common attitude is precisely worng. Formal mathematical technqiues have failed where they have been claimed to be paramount. The human understanding of beauty is an ability to function in the world by identifying what is most suited to an issue.Gelernter seems to be saying that the quest of many people to reduce the world to mathematics can only result in failure. It is confusing certainty with knowledge. Experience has shown that these technqiues cannot cope with real world complextity. The proponents of such techniques often portray themsleves as realisitc pragmatists who confront the problem which others try to avoid. Gelernter shows that these people are blind to the real problem and exhibit an unjustified faith in cold specific logic. Only techniques which can view the problem and proposed solutions holistically can hope to cope with real world complexity. It are these technqiues which supposed pragmatists heap scorn on which are most practical. It is poetry and not mathematics which bests describes the world.This book is worth reading.