One can expect the human race to continue attempting systems just within or just beyond our reach; and software systems are perhaps the most intricate and complex of man's handiworks. The management of this complex craft will demand our best use of new languages and systems, our best adaptation of proven engineering management methods, liberal doses of common sense, and a God-given humility to recognize our fallibility and limitations.

But I will argue that knowing complete product requirements up front is a quite rare exception, not the norm.

All programmers are optimists. Perhaps this modern sorcery especially attracts those who believe in happy endings and fairy godmothers. Perhaps the hundreds of nitty frustrations drive away all but those who habitually focus on the end goal. Perhaps it is merely that computers are young, programmers are younger, and the young are always optimists.

A scientist builds in order to learn; an engineer learns in order to build.

...when fits of creativity run strong, more than one programmer or writer has been known to abandon the desktop for the more spacious floor.

Even the best planning is not so omniscient as to get it right the first time.

Design work doesn't just satisfy requirements, it elicits them.