Amino acid metabolism and nutrition of farm animals continues to be an active area of research. However, since the publication of the first edition, as Amino Acids in Farm Animal Nutrition (1994), there is now a need to take into account advances in the amino acid nutrition of a wider range of animals, including companion animals. In this new edition, the editor has attempted to retain chapter imparting strength to the first version, while introducing authors with new ideas and vision, as well as chapters on other animals such as cats and dogs. The book is thematically structured. Part 1 includes chapter of an introductory and general nature with applications to a wide range of animal species. The next four parts are species-related sections, including pigs, poultry, ruminants and other animals. The chapters in the final section cover applications and perspectives. The book has been written as a reference work for advanced students as well as researchers in animal nutrition.