In the early 1960s, Fred Brooks managed the development of IBM's System/360 computer systems. After it was done he penned his thoughts in the book The Mythical Man-Month which became one of the most influential books on software development after its publication in 1975. Reading it in 2026, we'll find some of it outdated, but it also retains many lessons that are still relevant today.

The book contains Brooks's law: “Adding manpower to a late software project makes it later.” The issue here is communication, as the number of people grows, the number of communication paths between those people grows exponentially. Unless these paths are skillfully designed, then work quickly falls apart.

Perhaps my most enduring lesson from this book is the importance of conceptual integrity

I will contend that conceptual integrity is the most important consideration in system design. It is better to have a system omit certain anomalous features and improvements, but to reflect one set of design ideas, than to have one that contains many good but independent and uncoordinated ideas.

He argues that conceptual integrity comes from both simplicity and straightforwardness - the latter being how easily we can compose elements. This point of view has been a strong influence upon my career, the pursuit of conceptual integrity underpins much of my work.

The anniversary edition of this book is the one to get, because it also includes his even-more influential 1986 essay “No Silver Bullet”.