How can I copy or duplicate several objects in one step? I am building a tenement. After I have built one course of bricks I want to duplicate them to form an adjacent course, but with a negative scale, in the X axis.
When a story has been completed I want to duplicate this collection of courses and bricks, to create several stories.

I thought that parenting the first course of bricks to an empty would let me do this but it doesn’t.

How can I do it?
I was about to answer "Array modifier", but your case may be more complex. My way to accomplish this:


I make a separate scene just for one component (e.g. a window frame to be duplicated, or in your case, one full story), and model it there. 
After I'm done, I group it as one component.
Lastly, in the main scene, I instanced the group (Shift-A -> Group Instance) as many as I
needed. Each instances are free to be transformed.


Here's an example from a building I modeled, the original repeatable objects are collected in a scene for easy measurement control:



What I like about this approach, is that we can always modify the base component in its own scene, and all instances in the main scene will be updated. And unlike linked-duplicates, we can add as many object to the group as needed.