Here are some insights:
The Mythical Man-Month: Assigning more programmers to a project running behind schedule could actually make it even later.
The Second-System Effect: The second system an engineer designs is the most dangerous system he will ever design, since it will be disastrously overdesigned. Thus, when embarking upon a new project, a project manager should ask for a chief architect who has designed at least three or more systems.
Some humour: "They call this book the Bible of Software Engineering... and that's because everybody reads it but nobody does anything about it!"