My favourite quotes from The Mythical Man-Month

The Mythical Man-Month is an essay on Software Engineering and Project Management by Frederick Brooks based on his experiences at IBM while managing the development of OS/360. While he made mistakes he would later regret, seeing that many other managers fall through the same pittfals has led him to write this book and publish it in 1975.

Shortening birth by involving more women

When a task cannot be partitioned because of sequential constraints, the application of more effort has no effect on the schedule.
The bearing of a child takes nine months, no matter how many women are assigned.
Many software tasks have this characteristic because of the sequential nature of debugging.

Tasks involving communication take more time

Men and months are interchangeable commodities only when a task can be partitioned among many workers with no communication among them.
This is true of reaping wheat or picking cotton; it is not even approximately true of systems programming.

Involving new people slows down work initially

Adding manpower to a late software project, makes it later.

Delivering too soon

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.
The cook has another choice; he can turn up the heat.
The result is often an omelette nothing can save: burned in one part, raw in another.

Documenting stuff is hard

By documenting a design, the designer exposes himself to the criticisms of everyone, and he must be able to defend everything he writes.
If the organizational structure is threatening in any way, nothing is going to be documented until it is completely defensible.