"OOP to me means only messaging, local retention and protection and hiding of state-process, and extreme late-binding of all things. It can be done in Smalltalk and in LISP. There are possibly other systems in which this is possible, but I'm not aware of them."<p>Such a pity that this filtered essence about OOP was lost on me during formative years of learning OO-programming; for no fault of mine! It took me half a decade into professional programming in Java to realize the importance of these key concepts.<p>And the worse part is that most of the books/blogs start OO programming tutorial with examples that try to literally model the problem state using Objects (e.g., "Animals", "Shapes" etc.,).<p>I guess tutorials, classes just focus on these key goals and show how concepts such as "polymorphism", "inheritance" etc., are work towards achieving (or not) them. What generally happens is that one is taught about all these peripheral concepts and students are left to wonder the problems they are trying to solve.