The object-oriented paradigm is useful when building software systems where there is a hierarchy defined as a ranking or ordering of abstractions. - Grady Booch

… I pounded the doors at the local IBM sales office until a salesman took pity on me. After we chatted for a while, he handed me a Fortran [manual]. I'm sure he gave it to me thinking, "I'll never hear from this kid again." I returned the following week saying, "This is really cool. I've read the whole thing and have written a small program. Where can I find a computer?" The fellow, to my delight, found me programming time on an IBM 1130 on weekends and late-evening hours. That was my first programming experience, and I must thank that anonymous IBM salesman for launching my career. Thank you, IBM.

Every software system needs to have a simple yet powerful organizational philosophy (think of it as the software equivalent of a sound bite that describes the system's architecture)... [A] step in [the] development process is to articulate this architectural framework, so that we might have a stable foundation upon which to evolve the system's function points.

The class Dog is functionally cohesive if its semantics embrace the behavior of a dog, the whole dog, and nothing but the dog.