Reading about program structure?

I cut my teeth long ago with Visual Basic 6 while I was in highschool and continued programming so much in that I was using HTML, PHP, various scripting languages, and now Xojo on top of it all. Some of my internal software (I’m in entertainment production) have found success as commercial products.

As these products grow, I’m reusing more and more code and my coding is getting more complex, using more threads and so on. Is there any good language agnostic reading behind the design philosophies of modules, classes, how to keep their functionality as compartmentalized as possible, etc.? I feel like the classes I’ve been programming as I switch away from having all the code tied into GUI controls are still fairly sloppy.

Personally, I think the best thing to happen to my coding in all languages was to learn to write in Cocoa. Really forces the MVC model, which helped me think about class organization as a whole. YMMV, of course, but that was my personal experience.

My favorite is The Pragmatic Programmer. It is pretty short and easy to read.