In 1992, I published a book about aikido principles in Sweden. A few years ago, a German translation was released on the internet as a PDF file. Now, an English version of the book has just been published:
Aikido: The Peaceful Martial Art.
I made the translation into English, and took the opportunity of revising the text somewhat, but to my own surprise I found that most of it could be translated without any change. Either I have not developed as much as I should, or the ideas we have do not change as much through the years as we like to believe...
The book is not at all about aikido techniques and how they should be trained, but the principles and ideas behind them. As thoroughly as I can, I go through what is so special about aikido, how it differs from other martial arts, and what the basic concepts of it stand for.
When I originally wrote it, I was quite surprised to find how much of my personal philosophy and way of relating to life have been influenced by sweating and jumping around in an aikido dojo, not to mention the many thought provoking perspectives learned from the aikido teachers I have had through the years.
You cannot learn aikido through books, but at best they are stimulating material for the all-night talks we aikido students love to have after classes. That's how I hope my book will come to some use.
If you happen to come across the book, please let me know what you think about it.
Here is some more information about it:
http://www.stenudd.com/aikido/aikidobook.htm
And here it is at Amazon:
http://www.amazon.com/dp/1419658794/