[aryehof]

> "It's not about objects and classes, it's all about messages"

Often cited, but somewhat meaningless without the context in which Kay originally made that statement.

One should instead consider that object-orientation is "… the insight that everything we can describe can be represented by the recursive composition of a single kind of behavioral building block that hides its combination of state and process inside itself and can be dealt with only through the exchange of messages." - Alan Kay

It is primarily an approach to representing complex problems and systems in code. It is an alternative to modular programming (procedures and subroutines) organized using functional decomposition (structured programming), or an information or data-flow modeling approach. It is not primarily about organizing code.