James Adams begins with a history of technology and the engineering profession. The author next takes the reader on a guided tour of the engineer's world, beginning with design and invention - the part of engineering that generates new ideas. The next stop is in the field of mathematics, the discipline that allows engineers to build sophisticated products yet makes it a mystical enterprise to the lay public. Science and research, we learn, are the source of many creative directions in technology, but the interrelations between "basic" and "applied" professions are reciprocal and subtle. Experiment and testing introduce the trial-and-error aspect of engineering, which reduces, but can never eliminate, risk and failure. The author also covers manufacturing and assembly, practical processes that impose constraints on the idealistic inventions of the designer's mind; business and money, the latter being required to finance engineering and the former being the means for generating the money; and the controversial but inevitable role of technology regulation. "Flying Buttresses, Entropy and O-rings" aims to demystify a profession that is quite often taken for granted and to inspire an appreciation of the world of engineering.