The International Union for Conservation of Nature (IUCN) is the organization that issues the Red Data Book, a record of endangered species. The Red Data Book serves as a comprehensive guide to the conservation status of various species across the globe. It provides valuable information about the threats faced by these species and helps in formulating conservation strategies to protect them.

The Red Data Book is compiled by the IUCN's Species Survival Commission (SSC), which is the world's largest network of experts working towards the conservation of species. The SSC consists of thousands of scientists, researchers, and conservationists who assess the status of species based on extensive research and data collection.

The Red Data Book categorizes species into different levels of threat, ranging from "Least Concern" to "Extinct." This classification helps in identifying the most endangered species that require urgent conservation efforts. The book also provides detailed information about the species' distribution, habitat, population trends, and the main threats they face.

The IUCN Red List, which is a part of the Red Data Book, is widely recognized as the most authoritative reference for assessing the conservation status of species. It is used by governments, conservation organizations, and researchers worldwide to prioritize conservation actions and allocate resources effectively.

The IUCN plays a crucial role in promoting global conservation efforts. It collaborates with governments, NGOs, and other stakeholders to develop and implement conservation strategies. The organization works towards the sustainable use of natural resources and the preservation of biodiversity.

In conclusion, the International Union for Conservation of Nature (IUCN) issues the Red Data Book, which serves as a comprehensive record of endangered species. This publication plays a vital role in assessing the conservation status of species and guiding conservation efforts worldwide.

The Red Data Book, a record of endangered species, is issued by the "International Union for Conservation of Nature (IUCN)." This publication provides information on the status and conservation needs of various species worldwide, helping guide conservation efforts.