What exactly is “interface based programming”?

Question

I often hear/read about interfaced based programming but I am not exactly clear on what that really means. Is interfaced based programming an actual stand alone topic that

Answer 1

Chapter 6 of "Practical API Design" by Jaroslav Tulach is titled "Code Against Interfaces, Not Implementations". It explains that, by coding against an interface rather than a specific implementation, you can decouple modules (or components) in a system and therefore raise the system quality.

Bertrand Meyer in OOSC2 explains clearly why "closing" a system and making it more modular raises its quality.