Synopsis Iron pyrites is a mineral containing both iron and sulphur alongwith some micronutrients. Huge reserves of pyrites have been unearthed in various parts of the world. Pyrites has shown its potential as a multipurpose soil amendment, an acidifier, plant nutrient modifier and a cofertiliser to supply sulphur and iron to plants. The use of pyrites as an amendment, a recent development in the chemical amelioration of alkali soil, has opened fresh avenues in the reclamation of alkali soils. The book is a critical evaluation of the present knowledge on the oxidation of pyrites and factors affecting pyrites oxidation in soil, mechanisms of alkali amelioration through pyrites, pyrites use technology, agronomic management of alkali soils for improving the reclamative efficiency of pyrites, role of pyrites in improving the solubility of native and rock-phosphate P, besides use of pyrites as sulphur and iron carrier.