The programmer, like the poet, works only slightly removed from pure thought-stuff. He builds his castles in the air, from air, creating by exertion of the imagination. Few media of creation are so flexible, so easy to polish and rework, so readily capable of realizing grand conceptual structures.

Observe that for the programmer, as for the chef, the urgency of the patron may govern the scheduled completion of the task, but it cannot govern the actual completion. An omelette, promised in two minutes, may appear to be progressing nicely. But when it has not set in two minutes, the customer has two choices - wait or eat it raw. Software customers have had the same choices.

It is very difficult to make a vigorous, plausible, and job-risking defense of an estimate that is derived by no quantitative method, supported by little data, and certified chiefly by the hunches of the managers

I am more convinced than ever. Conceptual integrity is central to product quality.

Adding manpower to a late software project makes it later

Men and months are interchangeable commodities only when a task can be partitioned among many workers with no communication among them.

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