Tony Graham: Unicode: A Primer
A great intro.
Eight out of ten.
Essential for anyone working with Unicode.
This book is a very good introduction to the Unicode standards. Indeed, it goes lot further than just being an introduction. It contains a wealth of detail and a lot of very useful references. If you want to find out about Unicode and see how it will affect your work, this is the book to get.
If you are going to be getting stuck in to some serious Unicode based development work, you will need the official standards for some of the fine detail but you should also have a copy of this book as well. In that case, I'd expect that you would refer to this book a lot more than the standard.
After a short preliminary section that talks about the need for a standard and the standardisation process the meat of the book deals in "Part II" with the detail of Unicode and, in "Part III" with some practical uses.
The author explains things like the various UTF encodings for Unicode in a clear and readable style. He also provides a very useful set of cameos of the support for Unicode in various operating systems, programming languages and applications.
There then follow a substantial set of appendices charting the Unicode codings, the character sets used and so on.
I do have one criticism of the book. Despite the appendices, there is still a lot of material in the text itself that really should also be in the appendices. I'm thinking of things such as charts of mappings and details about the standardisation process. This is a minor complaint though and the reader will easily be able to step around these sections while progressing through the book.