>1) Each layer resides in is its own project? If so, would all 4 of these projects be part of a Customer solutuon, which then becomes part of the app's solution?

Solutions are not part of other solutions (in the sense of .sln files and Visual Studio). You *could* have many solutions working together if you wish to. Or not. That really doesn't matter. So, whether or not you separate this out into separate solutions is irrelevant pretty much.

We have lots of modules (projects) "in" one solution, and our solution's EXE is a pretty small file (modules are instantiated by Reflection ... let's not go there now <g>).

>2) It looks like a 'chain' of usage, IOW, WinUI.Customer uses Business.Customer which uses DataAccess.Customer which uses DataSets.Customer. Am I on track here?

Yes, but the DataSets can be pretty much used anywhere ... WinUI, Business and DataAccess.

>3) DataSets.Customer contains typed datasets?

Yes.

>4) Finally, I'm having a hard time visualizing a need for a BO layer in my app. Part of me wants to create it anyhow in case it's needed later, and even more just to segment things. What kinds of things do you put in your BO's?

It's a good idea to put it in there anyway. You never know what you might need to separate out. To go one step further, we have two kinds of Business classes ... server-side and client-side (we do everything through Web Services). So server-side Business classes are never used on the client-side (because they contain calls to DataAccess classes). Client-side Business classes can be utilized both server- and client-side.

>Thanks! I'm actually starting to understand all this. :)

Great! You're welcome! =0)

~~Bonnie