  In 2011, Rideau and Winskel introduced concurrent games and strategies as
event structures, generalizing prior work on causal formulations of games. In
this paper we give a detailed, self-contained and slightly-updated account of
the results of Rideau and Winskel: a notion of pre-strategy based on event
structures; a characterisation of those pre-strategies (deemed strategies)
which are preserved by composition with a copycat strategy; and the
construction of a bicategory of these strategies. Furthermore, we prove that
the corresponding category has a compact closed structure, and hence forms the
basis for the semantics of concurrent higher-order computation.
