There're some sources files in the book <ASP.NET Website Programming Problem-Design-Solution, Visual Basic.NET Edition>, take the file AppException.vb for example, its structure is as following:

Imports System
Imports System.Web
Imports System.Diagnostics

Namespace WebModules
  Public Class AppException
    Inherits System.Exception

    ... ... ...

  End Class
End Namespace

but in the responding class library Wrox.WebModules.Core.dll, the namespace WebModules is replaced by Wrox.WebModules which has a additional prefix Wrox, I wonder how the additional prefix Wrox comes.