The “Red Data Books” published by the International Union for Conservation of Nature and Natural Resources (IUCN) contain lists of threatened plant and animal species. These species are categorized according to the level of threat they face, such as critically endangered, endangered, vulnerable, etc. The purpose of these books is to draw attention to the conservation status of these species and to provide a basis for conservation action. The books also include information on the distribution, habitat, ecology, and threats to these species, as well as conservation measures that can be taken to protect them. The books are updated periodically to reflect changes in the status of the species and the effectiveness of conservation measures.