We review some aspects of the construction of self-dual gravity and the ass
ociated field theory of N = 2 strings in terms of two-dimensional sigma mod
els at large N. The theory is defined through a large N Wess-Zumino-Witten
model in a nontrivial background and in a particular double scaling limit.
We examine the canonical structure of the theory and describe an infinite-d
imensional Poisson algebra of currents. (C) 1999 Elsevier Science Ltd. All
rights reserved.