Rough and ready "compactness" I'm not going to take real analysis until next fall, but I don't know how I'll survive complex without knowing what "compactness" is. I've been working through a real analysis book with some success, but can anyone help me with web resources, or intuitive descriptions, of this concept? You could even suggest a good book. So, far I know that it is a property of regions. It's closely related to uniform continuity. On a closed compact set the same delta will work for all vales of Z. But why must it be closed? ... I'm finding this idea really hard to learn on my own.