The second ESSA Summer School in Social Simulation was held in Guilford, UK on 18-22 July 2011. The programme consisted of two lectures per day from experienced modellers, together with group sessions led by experienced researchers when participants discussed their modelling plans and experience. The faculty included Edmund Chattoe-Brown (University of Leicester, UK), Bruce Edmonds (Manchester Metropolitan University, UK), Nigel Gilbert (University of Surrey, UK), Klaus G Troitzsch (University of Koblenz, Germany), Pietro Terna (University of Torino, Italy) and Flaminio Squazzoni (University of Brescia, Italy), among others. The school was sponsored by the SIMIAN project, Unilever Plc. and the University of Surrey.