I configured the iBook to share its wired network connection through its Airport connection and gave the connection a name and password.
Nothing worked. The iBook didn’t show up on the list of iPad WiFi connections.
I tried to disable the built-in firewall on the iBook and got the error “other firewall software running.” This was wrong and a quick internet search came up with the solution to run “sudo ipfw flush” at a command prompt in a terminal window.
That did the trick and I was able to confirm that the firewall was disabled.
WiFi on the iPad still didn’t work.
Another quick check and it was apparent that the Airport sharing had not happened and I configured it again and made sure that I had clicked on the “start” button to start sharing it.
That did the trick for the Airport configuration and the iPad then showed the iBook in the list of WiFi networks. Entering the password finished the configuration on the iPad and I have now have very good WiFi in my office thanks to Apple having built-in WiFi in the iBook.
An unrelated issue that I discovered at the same time is that if the iPad is connected to iTunes through the USB cable then an app bought using the App Store app will sit on the home screen with a “waiting…” note and will not download. I unplugged the USB cable from the iPad and it immediately started using the WiFi to download the app.
Now I just need to make sure that the Airport WiFi sharing works while the iBook is sitting with the lid closed in what is probably a hibernation state.
Addendum
With the iBook lid closed, the sharing seemed disabled. This is a shortcoming in the iBook design but I can tolerate it since it lets me avoid buying a WiFi router for the office just for my rare and personal iPad use.