The current edition provides expanded information on the chemical composition of maize, including the makeup of maize protein and dietary fibre, on grain quality and storage and on the effects of lime-cooking of maize and the manufacture of foods such as tortillas, arepas and ogi. It reviews evidence of the association between maize consumption, bound niacin and pellagra and presents the evidence of amino acid deficiencies in maize and results obtained from experiments with both humans and animals. It discusses the importance of raising the protein quality of maize through incorporation of the opaque-2 gene and its probable contribution to improving the diet of maize-eating populations, and it makes a strong case for commercial production of quality protein maize (QPM). Finally, it provides a more up-to-date account of how maize diets can be improved following the old principle of nutrition: consume a balanced diet containing food legumes, animal protein, fruits and vegetables.