Its central theme is that adding manpower to a software project that is behind schedule delays it even longer.

This idea is known as Brooks's law, and is presented along with the second-system effect and advocacy of prototyping.

The most enduring is his discussion of Brooks's law: Adding manpower to a late software project makes it later.

When n people have to communicate among themselves, as n increases, their output decreases and when it becomes negative the project is delayed further with every person added.

Brooks insists that there is no one silver bullet: "there is no single development, in either technology or management technique, which by itself promises even one order of magnitude [tenfold] improvement within a decade in productivity, in reliability, in simplicity."

The author makes the observation that in a suitably complex system there is a certain irreducible number of errors.

Brooks wrote "Question: How does a large software project get to be one year late?

Incremental slippages on many fronts eventually accumulate to produce a large overall delay.

Continued attention to meeting small individual milestones is required at each level of management.

To avoid disaster, all the teams working on a project should remain in contact with each other in as many ways as possible (e-mail, phone, meetings, memos, etc.).

Additionally, Brooks muses that "good" programmers are generally five to ten times as productive as mediocre ones.