Folks, there is a newly published book out called "Discovering Aikido" written by Rupert Atkinson. Check it out at the following website:
http://discovering-aikido.com/
I've known the author for going on about 7 years now, and can say that he is quite knowledgeable about the topic of Aikido and the Martial Arts in general. If you look at the website you'll get a good gist of the book and I think you'll see it is one you'll want to acquire.