.-Preface.- Sum-product theorems and applications (Bourgain).-Can you hear the shape of a Beatty sequence? (Graham, O'Bryant).-Variance of signals and their finite Fourier transforms (Chudnovsky, Chudnovsky, Morgan).-Sparse sets in time and frequency related to diophantine problems and integrable systems (Chudnovsky, Chudnovsky, Morgan).-Addition theorems in acyclic semigroups (Cilleruelo, Hamidoune, Serra).-Small sumsets in free products of Z/2Z (Eliahou, Lecouvey).-A combinatorial approach to sums of two squares and related problems (Elsholtz).-A note on Elkin's improvement of Behrend's construction (Green, Wolf).-The postage stamp problem and essential subsets in integer bases (Hegarty).-A universal Stein-Tomas restriction estimate for measures in three dimensions (Iosevich, Roudenko).-The Erdos-Turan problem in infinite groups (Konyagin, Lev).-A tiling problem and the Frobenius number (Labrousse, Ramirez Alfonsin).- Sumsets and the convex hull (Matolcsi, Ruzsa).- Explicit constructions of infinite families of MSTD sets (Miller, Scheinerman).-Asymptotics of weighted lattice point counts inside dilating polygons (Nechayeva, Randol).- Support bases of solutions of a functional equation arising from multiplication of quantum integers and the twin primes conjecture (Nguyen).- Exponential sums and distinct points on arcs (Rodseth).- New Vacca-type rational series for Euler's constant g and its 'alternating' analog ln 4/p (Sondow).- Mixed sums of primes and other terms (Sun).- Classes of permutation polynomials based on cyclotomy and an additive analogue (Zieve).