After the Second World War, industrialization took place at a tremendous pace without giving any thought to its effects on the environment, ?ora and fauna, and people safety and health. This led to major environmental problems. Industries are now interested in green chemistry because reduction in energy, improvement in yield, and use of cheaper raw materials lead to reduction in working capital and an increase in pro?t; also they are interested in improving the safety, health, and working conditions of their workforce. Incremental improvements in processes are easily implementable, while major changes in processes require changes in equipment and hardware; therefore the manufacturing industries hesitate to undertake such a huge capital expenditure. On the other hand, preventing or reducing waste at the source through design of innovative processes is much more pro?table for them. This book is an interdisciplinary treatise dealing with chemistry and technology of green chemistry. Measuring “greenness” has always been a challenge and there are different approaches discussed here. Comparing various processes based on a set of common standards is discussed.