This is volume 4 of the truly Brobdingnagian "mother of all birdbooks", the Handbook of the Birds of the World. Known as the HBW for short, this 16-volume work took almost 20 years to publish, and apparently a supplement with is still waiting in the wings (pun intended). The total price of the entire series is about 4,200 dollars!
Obviously, the HBW is mostly intended for well-funded libraries and research institutions. In contrast to regular reference works, however, the HBW contains a lot of truly spectacular photos (all of them in color), plus illustrations of all described species (also in color). I'm not sure if this combination of commercial appeal and super-scientific contents makes any kind of sense, but clearly *somebody* is buying it, since the editors were allowed to finish their work. As we speak, they are busy preparing a Handbook of the Mammals of the World!
This particular volume of the HBW covers the following orders: Sandgrouse, Pigeons and Doves, Cockatoos and Parrots, Turacos and Cuckoos. With the possible exception of the Sandgrouse, these birds hardly need a closer introduction.
As usual, the HBW deserves five stars, although I must once again warn the general reader about the non-popularized character of this work and the exorbitant price. However, if you have an advanced interest in birds (and a lot of money!) don't worry, you won't feel cuckolded if you really do buy one of these...