Greetings all, I would like to draw your attention to a book I have found useful. The Reiki Sourcebook by Bronwen and Frans Stiene has the most up-to-date information I have found on the origins of Dr Usui's method and the historical context it arose in, as well as some excellent links and references to other sites/sources. It also includes an extensive glossary. It is what it says, a sourcebook : it doesnt offer new teachings or methods, though the descriptions of a wide range of existing techniques would be useful to any practitioner not already familiar with them.
Worth the asking price.
Skyhorse.