Brook's law
An outrageous oversimplification that states "Adding manpower to a late software project makes it later"
The Mythical Man-Month
Essays on Software Engineering is a book on software engineering and project management by Fred Brooks first published in 1975, with subsequent editions in 1982 and 1995. 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