Jewels of the canopy, the leaf warblers of the genus Phylloscopus are high on any birder's wishlist. Often greenish above and yellowish below, this group of often tiny birds ticks so many boxes – the subtlety of wing-bars and eyebrow stripes, some of the sternest identification challenges in the birding world, and often distinctive and sometimes beautiful vocalisations, although some species can only be reliably separated by tiny variations on call. They are the ultimate 'birder's birds', with many species being long-distance migrants (and therefore vagrants).

With 81 species (including those formerly considered part of Seicercus), almost all of which breed in the Palearctic and Oriental zoogeographical regions, there is a vast literature on Phylloscopus systematics and taxonomy, breeding ecology, habitat use, identification and conservation, with particularly striking recent advances in our understanding of migration patterns. This is brought together in this magnificent work, Leaf Warblers, written by an international team of leading ornithologists led by Vincent van Der Spek. This is the first monograph of the leaf warblers ever published.

The rich detail of the species accounts is accompanied by accurate maps showing races and migration routes, photographs of age variation and all major taxa, QR codes to representative songs and calls, and an astounding colour plate section by Faansie Peacock. At more than 640 pages, this is the ultimate reference work to these birds, and an essential addition to any birder's bookshelf.