how can i share iBooks with my wife's iPad?

I read different approaches on this site, and tried a couple of them, to no avail.

Here's what finally worked for me:

I logged into my iTunes account (which backs up my iPad2). I jumped out to Finder, created a New Folder called Books. Then I went back to the ITunes window, clicked on iBooks, and then one by one dragged the books my wife wanted into the folder.

Next, I inserted a thumbdrive, and dragged the Books folder from my desktop to the thumbdrive.

Finally, my wife logged into her account and opened ITunes, plugged in her iPad mini, went to File > Add to Library, and highlight the thumbdrive, and then the folder Books, and clicked on it.

All of my iBooks then transferred to the iPad mini's collection. A few steps, but pretty fast and easy.