This is the USA version (although the book does not cover most North American species!).
The European version is 'Birds of the Palearctic: Passerines' by Collins. Hardback and costing 50% more than the USA version. It's been out now about 2 months.
Note the European version does not cover all the birds seen in Hong Kong because the definition of Palearctic does not cover South China, I would say about 95% of HK birds are included (only passerines, as the title says). So, if the USA version is the same as the European (and the number of pages, 240, is the same), it does not fully cover China from the Yangtse south. But most HK passerines are there.
The great thing about it is its size - just larger than a pocket notebook, very light and easy to carry. The negative for this is, the illustrations do not include any juvenile/immature/first winters. Also almost no text descriptions except on voice and behaviour.
I like it because of its size and it also brings together in one book the species of Europe, Russia and North Asia. The maps are quite interesting, not sure if they are entirely accurate. The illustrations seem good although quite small. Also it's not too expensive.
The non-passerine version is supposed due out later this year.
