Rex Bills' Rulership Book is basically a collection of 4 lists:
The first one is an alphabetical list of all kinds of nouns, objects, concepts, etc., right next to which is a reference to the planet, sign or house that rules that particular thing. The second one is a listing by planets. It goes through each planet and lists alphabetically all things ruled by that particular planet. The third and fourth lists follow the same line, with listings by signs and houses. In the end of the book, there is also an appendix with special listings, such as bones of the body, muscles, flavors, etc.

This is a thorough and excellent compilation of rulerships. If you are a beginner, it may not make much sense to buy such a book, since it doesn't mean that much to know that "isolation" is ruled by Saturn for example, if you can't comfortably read a chart yet. You wouldn't know what to do with information like this. I think it's better suited for advanced learners. If one studies astrology seriously, sooner or later they will definitely need a book with rulership listings, and believe me, currently there are no better books on the subject than this one, even though it was first published in 1971... I use it mostly in special astrological topics, such as vocational and business astrology and I find that it is especially useful in horary and electional astrology.

This book is an extensive collection of planetary, sign and house rulerships that you will wish you had had long before your purchase. Want to know what planet/sign rules a Foundation? a Charitable Trust? Radio Broadcasters? Satellites? You'll find them in this book along with many more rulerships some well known, but many more obscure but never-the-less useful in your astrology work. I bought it as a result of a recomendation by a well known astroger - and they were right on target as I would have suspected!