The Red Lists are the most comprehensive and authoritative global surveys of threatened species in existence. They identify taxa that are most threatened, thereby serving as tools to help to set priorities for conservation action and providing baseline information for monitoring status of taxa. The Red Lists provide a framework for more specific information about taxa under threat—such as national or regional lists and conservation strategies—and alert regions, nations, and communities to taxa of international conservation concern. The Red Lists are the technical resource to international legal instruments and are frequently used to create and strengthen national species protection Laws. Periodical revisions of these lists are issued from time to time.

        The latest version of the Red List of Threatened Animals has been released in 1996 and another version is due in 1999.

       The first ever IUCN Red List of Threatened Plants of 1997, containing 33,798 species names the threatened category, was released in April 1998, simultaneously from Washington, London, Canberra and Cape Town (Sowdowski, 1998). The listed species belong to 369 plant families and 200 countries. They constitute 12.5 per cent of known species of vascular plants. The publication of this list is a turning point in plant conservation.

        Red Data Books of the IUCN provide in-depth analyses of the conservation status of particular groups of species. Earlier, Red Data Books cited 60,000 plant species as endangered. Certain situations of species make categorisation of their conservation status difficult. For example, the African Violets (Saintpaulia ionantha) are the most popular house plants throughout the world. But, a few years ago, an expedition found only three individuals in its wild habitat in Tanzania (Donellan, 1995). The species is certainly endangered in the wild but is abundant in cultivation. Similarly, the Indian Asoka tree (Saraca asoca) has definitely become rare in the wild but is a common avenue tree in many places in the country. Often, a distinction needs to be made between taxa that are threatened only in the wild habitats and those which are at total risk. Some species, such as Tribulus terrestris, which are under threat in one locality may be abundant in another.

       Like several other countries in the world, Red Data Books have been published from India. Unfortunately, for plants the lists of threatened species have been based on the records of herbarium specimens of the concerned species, found in different herbaria in the country. This is an unscientific criterion as often the most abundant species comes to be sparsely represented in herbaria. The Indian Red Data Books have generally become suspect and questioned in International fora, as they were not based on valid criteria. Consequently we need to revise the Red Data Books of Plants in India on scientific methods. This work is now being carried out at the Indira Gandhi Conservation Monitoring Centre associated with the WWF-India, at New Delhi.