  These talks present an overview of a tentative theory of large distance
physics. For each large distance L (in dimensionless units), the theory gives
two complementary descriptions of spacetime physics: quantum field theory at
distances larger than L, string scattering amplitudes at distances smaller than
L. The mechanism of the theory is a certain 2d nonlinear model, the
lambda-model, whose target manifold is the manifold of general nonlinear models
of the worldsurface, the background spacetimes for string scattering. So far,
the theory has only been formulated and its basic working described, in general
terms. The theory's only claims to interest at present are matters of general
principle. It is a self-contained nonperturbative theory of large distance
physics, operating entirely at large distance. The lambda-model constructs an
actual QFT at large distance, a functional integral over spacetime fields. It
constructs an effective background spacetime for string scattering at
relatively small distances. It is background independent, dynamically. Nothing
is adjustable in its formulation. It is a mechanical theory, not an S-matrix
theory. String scattering takes place at small distances within a mechanical
large distance environment. The lambda-model constructs QFT in a way that
offers possibilities of novel physical phenomena at large distances. The task
now is to perform concrete calculations in the lambda-model, to find out if it
produces a physically useful QFT.
