Preface to the Workshop on Algorithm Engineering and Experiments; Preface to the Workshop on Analytic Algorithmics and Combinatorics; Workshop on Algorithm Engineering and Experiments. Computational Challenges from the Tree of Life, B.M.E. Moret; Drawing Graphs to Speed Up Shortest-Path Computations, D. Wagner and T. Willhalmy; Computing Point-to-Point Shortest Paths from External Memory, Andrew V. Goldberg and Renato F. Wernecky; An Experimental Analysis of Change Propagation in Dynamic Trees, Umut A. Acar, Guy E. Blelloch, and Jorge L. Vittes; Flows over Time: Towards a more Realistic and Computationally Tractable Model, Alexander Hally and Heiko Schillingz; Solving the Prize-Collecting Steiner Tree Problem to Optimality, Ivana Ljubi'c, Rene Weiskircher, Ulrich Pferschy, Gunnar Klau, Petra Mutzel, and Matteo Fischetti; An Incomplex Algorithm for Fast Suffix Array Construction, Klaus-Bernd Schurmann and Jens Stoye; Better External Memory Sux Array Construction, Roman Dementiev, Juha Karkkaineny, Jens Mehnertz, and Peter Sanders; Counting and enumerating pointed pseudo-triangulations with the greedy flip algorithm, Herve Bronnimann, Lutz Kettner, Michel Pocchiola, and Jack Snoeyink; Hardware-Assisted Natuaral Neighbor Interpolation, Quanfu Fan, Alon Efrat, Vladlen Koltun, Shankar Krishnan, and Suresh Venkatasubramanian; Approximating the True Evolutionary Distance Between Two Genomes, Krister M. Swenson, Mark Marron, Joel V. Earnest-De Young, and Bernard M.E. Moret; On the Adaptiveness of Quicksort, Gerth Stolting Brodal, Rolf Fagerberg, and Gabriel Moruz; How Caching Affects Hashing, Gregory L. Heileman and Wenbin Luo; Extending STL maps using LBSTs, Leonor Frias; An Experimental Study of Different Approaches to Solve the Market Equilibrium Problem, Bruno Codenotti, Benton McCune, Sriram Pemmaraju, Rajiv Raman, Kasturi Varadarajan; A New Decoding Algorithm for Statistical Machine Translation: Design and Implementation, Tanveer A. Faruquie, Hemanta K. Maji, and Raghavendra Udupa U.; Workshop on Analytic Algorithmics and Combinatorics; Performance evaluation of demodulation with diversity: A combinatorial approach III: Threshold analysis, S. Bliudze and D. Krob; Comparison of Two CDS Algorithms on Random Unit Ball Graphs, Jennie C. Hansen and Eric Schmutzy; Complexity of the Path Multi-Peg Tower of Hanoi, Daniel Berend and Amir Sapir; Mixing Points on an Interval, Dana Randall and Peter Winkler; Enumeration of Binary Trees, Lempel-Ziv'78 Parsings, and Universal Types, Charles Knessl and Wojciech Szpankowski; On the Average Density and Selectivity of Nodes in Multi-Digit Tries, Yuriy A. Reznik; Mixing Times for Random Walks on Geometric Random Graphs, Stephen Boyd, Arpita Ghosh, Balaji Prabhakar, and Devavrat Shah; Counting Structures in Grid Graphs, Cylinders and Tori Using Transfer Matrices: Survey and New Results, Mordecal J. Golin, Yiu Cho Leung, Yajun Wang, and Xuerong Yong; Counting Eulerian Circuits is No. P-Complete, Graham R. Brightwell and Peter Winkler; Approximately Counting Perfect Matchings in General Graphs, Martin Furer and Shiva Prasad Kasiviswanathan.