Currently including more than 380,000 species, beetles are by far the most speciose of all Orders and represent nearly one fourth of our planet's known biodiversity. With a total of ~66,000 described extant species, rove beetles (Staphylinidae) are probably the most biodiverse family - not only of beetles - but of all organisms on Earth, and hundreds of new species are added every year. Staphylinidae are distributed worldwide and remarkably ecologically diverse. They are found in practically all terrestrial habitats from wet to arid, from sea-level to high-alpine, and from deep soil to the canopy layer of forests. Numerous species are inquilines living with ants, termites, wasps, mammals, and birds or inhabitants of mushrooms and various kinds of decaying matter such as compost, dead wood, carrion, and animal excrements. Despite the important role of rove beetles in practically all terrestrial ecosystems, relatively little is known about their life histories and ecology.

The present monograph revises the hyperdiverse genus Palaminus Erichson, 1839, part of the paederine subtribe Procirrina with formerly 770 known species that are widely distributed in tropical and subtropical forests around the world. The genus has been represented by 309 valid species and two subspecies so far. The majority of the species was described from the Neotropical and Nearctic Regions (141 species), and the Afrotropical Region including Madagascar and neighbouring islands (117 species). The Palearctic, Oriental, and New Guinean fauna of the genus Palaminus was previously represented by only 36 species, while 14 species were known from Australia and the Pacific Islands. The genus had never been the subject of a comprehensive revision. As a result of the present study, the genus is now represented in the Palaearctic and Oriental regions, including New Guinea, by as many as 367 species, including 335 new species. In addition, species from the Pacific islands of New Caledonia, Vanuatu, Fiji, Guam and Samoa are revised and seven new species are described from the area. All the species are (re-)described and illustrated. With few exceptions, the distributions of all the species in the study region are mapped.

Several other taxonomic acts are also proposed, such as four species synonymies, two name revalidations and fourteen lectotype designations. A comprehensive catalogue of the species of Palaminus of the Palaearctic and Oriental regions, Wallacea and some Pacific Islands is provided.