Headed by Principal Investigator Glynn Winskel, the project ECSYM assembles a world-leading team of theoretical computer scientists and mathematicians. Their goal: to build the next-generation semantics---a new mathematical foundation with which to understand and analyze computation of the complexity we begin to see today. The proposal arises in answer to the anomalies found in today's theories of computation and to the commonality and need for shared techniques becoming apparent across a range of seemingly disparate areas, through security protocols, systems biology, model checking, computational games, types and proof.The evidence points to a new intensional semantics, one in which the current distinctions between operational and denotational semantics disappear. It leads to the project ECSYM (Events, Causality and SYMmetry). The project marries the vision of Scott and Strachey, who sought a comprehensive semantics of computation, with Petri's analysis of computation, as emergent from local causal structure between basic events. A key insight is the increased expressivity a treatment of behavioural symmetry brings to causal models, to the types, processes, operations and applications they can support.