Neem is a fascinating tree. On the one hand, it seems to be one of the most promising of all plants and may eventually benefit every person on the planet. Probably no other yields as many strange and varied products or has as many exploitable by-products. Indeed, as foreseen by some scientists, this plant may usher in a new era in pest control, provide millions with inexpensive medicines, cut down the rate of human population growth, and perhaps even reduce erosion, deforestation, and the excessive temperature of an overheated globe.On the other hand, that all remains only a vague promise. Although the enthusiasm may be justified, it is largely founded on empirical or anecdotal evidence. Our purpose here is to marshal the various facts about this little-known species, to help illuminate its future promise, and to speed realization of its potential.This report has been produced by the National Research Council particularly for nonspecialists such as government ministers, research directors, university students, private voluntary organizations, and entrepreneurs. It is intended as an economic development document, not a scientific monograph.