Book excerpt: Soils with high Ni contents occur in several parts of the world, especially in areas with ultramafic rocks which cause serious environmental impacts. This book aims to extend the knowledge on the risks and problems caused by elevated Ni contents and to cover the existing gaps on issues related to various aspects and consequences of high Ni contents in soils and plants. Nickel in Soils and Plants brings together discussions on Ni as a trace element and as a micronutrient essential for plant growth and its role in plant physiology. It analyzes the biogeochemistry of Ni at the soil plant interface, and explains its behavior in the rhizosphere resulting in Ni deficiency or toxicity, or Ni tolerance of various Ni hyperaccumulators. Included are Ni resources and sources, the origin of soil Ni, its geochemical forms in soils and their availability to plants, a special reference on soils enriched with geogenic Ni, such as serpentine soils, and the special characteristics of those ecosystems. Recent advancements in methods of Ni speciation, including the macroscale and X- ray absorption spectroscopy studies as well as serious views on Ni kinetics, are also covered. Written by a team of internationally recognized researchers and expert contributors, this comprehensive work addresses the practical aspects of managing Ni in soils and plants for agricultural production, and managing soils with high Ni levels by using organic and inorganic amendments. The text also addresses practical measures related to Ni toxicity in plants, the removal and recovery of Ni from high Ni wastes, and offers environmentally friendly innovative processes for mining Ni from soils containing high Ni levels.