[Zope-dev] ZPatterns: DropZone example

[Jimmie Houchin]

"Phillip J. Eby" wrote:
[snip]
> Peter Coad's design approach (which ZPatterns is heavily based on/biased
> towards) emphasizes four major layers of classes in an application:
> 
> 1) User Interface (GUI, forms, etc.)
> 2) Problem Domain (the actual application purpose)
> 3) Data Management (object persistence/lifecycle management)
> 4) System Interaction (interfaces w/hardware or other software)

Is this from one of his books? If so, which one? 
I would be interested in gaining more enlightenment. :)

Thanks,

Jimmie Houchin