iBooks Author is beautiful but you can only use it to sell through Apple iBookstore

The license agreement to Apple's new iBooks Author tool for creating electronic textbooks has a very peculiar clause:

If you charge a fee for any book or other work you generate using this software (a “Work”), you may only sell or distribute such Work through Apple (e.g., through the iBookstore) and such distribution will be subject to a separate agreement with Apple.

I find that clause unacceptable and ridiculous. If I create a book, I want to be able to sell it anywhere I want, not only through Apple. I no more want to restrict my sales to their store than I want to restrict them on Amazon or anywhere else.

Frankly, I even find it insulting.

You can find the full license agreement by going to the iBooks Author menu, choose About iBooks Author, and then click License Agreement in the About box that appears.

Note that it didn't have to be this way. The files that iBooks Author creates are pretty reasonable EPUB files (masked with the .ibooks extension) and can be read in NOOK and other EPUB readers. You can unzip them and see the EPUB files inside.

I am very disappointed.