Design techniques of approximation algorithms: greedy algorithms and local search, rounding data and dynamic programming, linear programming relaxations. Example problems: Vertex Cover, Set Cover, Metric Steiner Tree and TSP, Knapsack, Bin Packing. (A larger course with the same name was given in 2010.) Prerequisites: the course Design and Analysis of Algorithms or equivalent. Course book: D. P. Williamson, D. B. Shmoys: The design of Approximation Algorithms, Cambridge University Press, 2011.