Nickel (Ni), the fifth common element on the earth is widespread in the environment. Recently Ni has been proved essential for normal growth of many organisms, and at the same time Ni can become toxic to organisms when high in concentration. In several parts of the world, high Ni concentrations are causing serious environmental impacts. This book will be the first to discuss the problems related to Ni presence and raise the need for full investigation and more efforts to support this goal. It will present the recent advances in research on Ni nutrition of plants, Ni contamination of the environment–that is, soils, waters and plants–and methods of remediation.