A Fantastic Reference Book!
I attended the Electronex Conference in Sydney about a month ago and whilst there visited the Würth Electronik stand where I saw a selection of their products and this fascinating reference book on display.
The book was so good that I purchased it on the spot. It's called "Trilogy of Magnetics - 4th edition"
It contains loads useful of technical information that is clearly articulated.
It is presented in 4 separate sections;
Basic Principles
Components
Applications
Appendices.
Unlike my old university Electromagnetic textbooks, this publication contains lots of useful and current information making it a must for any serious designer.
Here's a link for more information.
http://www.we-online.com/web/en/passive_bauelemente_standard/download_center_pbs/Trilogie.php
There is also a sister book called the Trilogy of Connectors. I haven't read it but based upon the quality of this book and online extracts I must get a copy of it soon.