This is the Daddy of name books, which all others should tremble before.
Your average name book will give you the name, assign it an often arbitrary nationality, and give it a one word "meaning". Not the Oxford. Here you get the etymology, origin and history of each name, and information on its usage. It also tells you the international forms and nicknames. They have clearly put in the research; I have never spotted a factual error in it.
It's organised alphabetically, without splitting into 'girls' names' and 'boys' names'; instead, it puts either a male symbol, a female symbol or both next to the name, explaining the changing usage patterns of a "unisex" name such as Shirley or Taylor. It's British but tells you whether a name is particularly popular in, say, America or Australia.
It also includes appendices of names from lots of other languages, including for example Welsh, Arabic, Spanish and Scandinavian, although the information in the appendices is less detailed and of course, fewer names are included as there would hardly be room for every name in every country. It often cross-references from the main dictionary to an appendix, e.g. Declan will send you to Deaglan in the Irish section.
As if all that wasn't enough! It also includes lists of the most popular names circa 2004 in most English speaking countries, and an overview of what names have been popular in previous decades.
Informative guide for parents and also very readable for those interested in names to flick through or use as a reference guide.
And extra props for not having a picture of a baby on the front, or indeed the word 'baby' - not everybody interested in names is pregnant!