Code That Fits in Your Head

Mark Seemann is known for explaining difficult programming ideas with clarity and depth. Drawing on decades of work with software teams, he offers hands-on methods for producing code that people can understand and keep working on for years. The book focuses on keeping complexity in check so that projects do not buckle under their own weight.

Beginning with an empty repository, Seemann takes the reader through building a feature from start to deployment. Along the way he covers how to maintain a steady pace while adding functionality, how to handle cross-cutting concerns, and how to troubleshoot and optimize.

The chapters cover checklists, teamwork, encapsulation, decomposition, API design, and unit testing. Seemann illustrates these topics with code from a complete sample project written in C#, but the ideas apply to any object-oriented language, including Java, C++, and Python. The source code and detailed commit messages are available for download.

The book is aimed at developers who have struggled through failed projects or inherited legacy systems that are hard to maintain. It shows readers how to pick workable mindsets, avoid misleading metaphors, escape endless up-front analysis by delivering a thin end-to-end slice of an application, resist the gradual decay of code, change behavior more safely, and think clearly about performance and security.