We propose here that understanding the history of lineages and ecosystems is a prerequisite to developing effective conservation programmes. Short-term perturbations (i.e., those documented within the last two centuries) may alert us to short-term problems but comprehension of long-term trends requires a prehistoric perspective at least millennia in length. Modem ecological studies alone cannot provide this perspective. Understanding of the fossil record should enable us to: recognize long-term cycles of extinction; determine the long-term “health” of lineages (i.e., identify those that are in decline, on the rise or stable); improve the success rate of introducing endangered animals into new or formerly occupied habitats; qualify the relative conservation importance of threatened animals; identify modern habitats that have lower than potential species diversity; recognize long-term patterns in interspecific associations of animals (e.g., incompatible vs tolerant vs obligate relationships); and distinguish non-human from human factor s promoting change in lineages or ecosystems. Extinction in and conservation of communities steadily diminishing in size and diversity may become anachronisms that must give way to preservation.