The Advanced Day Planner User's Guide by Hyrum W. Smith – Published by Franklin International Institute, Inc – ISBN 0-939817-001-2
First of all, this book is not written with the Filofax in mind... so before I get your expectations up, I thought I best say that first. However, whilst the Franklin Day Planner is a rival to Filofax, a lot of the principles and ideas are transferable to the Filofax system.. so it's worth a look.
The book takes the form of suggestions and ideas sent in by users to Franklin International and there are 83 different suggestions in total, all nicely explained and illustrated in the book which is over 175 pages in total.
I've been working my way through the book looking for new ideas that I could use in my Filofax. As has been mentioned previously in a comment on this blog a while back, there is nothing earth shattering in the book, but there are a few good ideas. You don't really need to read it from cover to cover even, just open it when you have a few moments to kill and read one of the suggestions. Each one is complete and it doesn't require you to read all the others.
Some of the suggestions refer to specific Franklin Day Planner Forms, some of these are similar to those available for Filofax but there are some that could be adapted to different Filofax sizes and may be slightly different layouts according to the size of the binder you are using.
One of the nicer touches about the way the book is written is the way in which the suggestions are described. How they came about from real life situations. So it is easier to see how the problem was solved and how the form or suggestion solved the problem and may be how you might use a similar suggestion for a similar problem of your own.
I picked up this book on Amazon Marketplace for less than £5 including postage, it was published back in 1987, which was about the time that planners and organisers where becoming very popular. So I suppose there was demand for such a book at the time. I'm not sure such a book these days would sell a lot of copies... this blog and other associated websites are most probably a better sources of information.
So if you are interested in reading more, I'm not sure if this book will be in your local public library, or take a look at Amazon, there were plenty of copies available when I purchased mine.