  P. Winter. Steiner problem in networks: A survey. Networks, 00:000-000, 0000.MathSciNetCrossRefMATH  M. Yagiura and T. Ibaraki. Local search. In P.M. Pardalos and M.G.C. Resende, editors, Handbook of applied optimization, pages 000-000. Oxford University Press, 0000. © Springer Science+Business Media New York 0000  Mauricio G.C. Resende and Celso C. RibeiroOptimization by GRASP00.0000/000-0-0000-0000-0_0  # 0. A short tour of combinatorial optimization and computational complexity  Mauricio G. C. Resende0  and Celso C. Ribeiro0  (0)  Modeling and Optimization Group (MOP), Amazon.com, Inc., Seattle, WA, USA  (0)  Instituto de Ciência da Computação, Universidade Federal Fluminense, Niterói, Rio de Janeiro, Brazil  This chapter introduces combinatorial optimization problems and their computational complexity. 