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Hacker Laws

Hacker Laws is a collection of the most essential patterns, principles and concepts for engineers. They are even more essential in the age of AI, where judgement about system design, complexity, delivery and architecture are the most essential skill that an engineer brings to a project.

These are laws such as:

  • Gall's Law: "A complex system that works is invariably found to have evolved from a simple system that worked."
  • Kernighan's Law: "Debugging is twice as hard as writing the code in the first place."
  • Premature Optimization: "Premature optimization is the root of all evil."

This project has been a popular read for many years. It's now getting a full refresh and update ready for the next edition, with real-world examples that are even more applicable as agentic engineering is changing how we build software.

Top ten laws​

These are the laws I think are the most valuable to look at first. You can also choose Random law from the toolbar, browse by category on the left, or see all the laws in one place:

  • Gall's Law - Working complex systems evolve from working simple systems.
  • The Law of Leaky Abstractions - Every useful abstraction eventually exposes some of what it hides.
  • Hyrum's Law - Someone will depend on every observable behaviour of a widely used system.
  • Conway's Law - Systems tend to reflect the organisations that build them.
  • Brooks' Law - Adding people to a late software project can make it later.
  • Hofstadter's Law - Work takes longer than expected, even when delays are expected.
  • Goodhart's Law - A measure stops being useful when it becomes a target.
  • Kernighan's Law - Clever code is harder to debug than it is to write.
  • Chesterton's Fence - Understand why something exists before changing or removing it.
  • All Models Are Wrong - Models are imperfect, but they can still be useful.

Developers from around the world have contributed to the project, and volunteers have translated it into thirteen languages. Raise an issue if you have a question, idea or concern.

Like my book Effective Shell, Hacker Laws is free to read online. I am also working on a print version.