With only two volumes to go, following this one, how the editors have managed to keep to such a very tight production schedule is nothing short of astonishing. This volume (and the next one) will be of particular interest to African birders as it contains bushshrikes, helmetshrikes, vangas, drongos, crows, starlings and Old World sparrows, although there are several other families, mainly Australasian endemics, including the bowerbirds and birds-of-paradise. (Vol. 15 will include weavers, waxbills and finches.)
The format must be well known to just about everyone by now. For each family a comprehensive essay discusses taxonomy, ecology, behaviour, conservation and relationships with humans, all accompanied by a series of usually stunning photographs, many of which involve birds engaged in 'interesting' behaviour, i.e. they are not merely portraits. This is followed by the individual species accounts accompanied by a series of excellent plates (by several artists). These are set out in a simple and clear format under a series of main headings.
The taxonomy is commendably up to date and treads a reasonable course between 'splitting' and 'lumping'. For example, it is noted that Bulo Burti Bushshrike Laniarius liberatus is now thought to be a colour form within the Tropical Boubou L. aethiopicus complex, but L. erlangeri (containing 'liberatus') and L. sublacteus are split, while L. major is not. The series has, almost inevitably, been 'caught out' by some advances in taxonomy during the course of its publication. For example, several Malagasy endemics whose affinities have been debated for many years, such as the four species of Newtonia and Ward's Flycatcher Pseudobias wardi, were covered as warblers or flycatchers in earlier volumes. These are now usually considered vangas and would therefore, as noted in the relevant section, be better placed there.
As usual, the Foreword takes the form of an essay on a topical subject, this time the history and development (past, present and future) of birding by Stephen Moss. It has a global perspective, with sections on the early history, developments through the 20th century, the rise of citizen science and the impact of amateurs on scientific research and conservation, as well as the economic benefits of birding (which is being extensively promoted in several parts of Africa).
Overall the series is superb. Although quite costly to an individual, there is usually a good pre-publication offer. I doubt that such a work will ever be repeated in this form and if you need a comprehensive review of the world's birds then there is no other choice.