Barbara Liskov

"A type system is a form of discipline that prevents careless mistakes before they happen."

"The most powerful abstractions are those that hide the irrelevant while revealing the essential."

"When you find yourself writing special cases, you've usually misunderstood the underlying problem."

"Programming is the art of managing complexity through layers of carefully chosen abstraction."

"The code you write today will be read and modified thousands of times; write it as if someone you respect will judge you by it."

"Innovation in software comes not from adding features, but from discovering simpler ways to express intent."

"Every bug in a deployed system represents a failure of our abstractions, not of users."

"The best designs are those that make the right way also the easiest way."

"Modularity is not an end in itself; it's a means to managing the complexity of human understanding."

"When your code requires extensive documentation to explain what it does, reconsider the design."

"A system's architecture should reflect the conceptual model of the domain, not the implementation details."

"The most important part of software design happens before you write the first line of code."

"Elegance in design often comes from removing what you don't need, not adding what you think you might."

"To design well, you must first understand deeply; understanding comes before clever solutions."

"Polymorphism is not a feature to use everywhere; it's a tool for expressing meaningful variation."

"The interfaces between components are where most of the learning about a system actually happens."

"A good design principle is one that guides you away from problems, not one that sounds profound."

"Reusability doesn't come from trying to anticipate every possible use; it comes from deep understanding of principles."

"The coupling between components should be minimal; their cohesion should be maximal."

"When you find yourself arguing about implementation details, it's usually a sign that your abstractions are wrong."

"Software systems, like organisms, grow and change; design them accordingly."

"The most reliable systems are those where failure modes are visible and understood."

"A type-safe system catches many mistakes that would otherwise hide in dark corners of the code."

"Design is not decoration; it's the underlying structure that makes everything else possible."

"The programmer who understands the domain deeply will write better code than one who only knows the language."

"Constraints in design are not limitations; they are guides to finding the essential structure."

"When your system requires less code to express the same idea, you've usually made progress."

"The greatest designs teach you something about the problem domain itself."

"Complexity is not the price of functionality; it's often the price of poor choices."

"A program that works today but is incomprehensible tomorrow will fail again when it must change."