  Recent developments in string theory suggest that string theory landscape of
vacua is vast. It is natural to ask if this landscape is as vast as allowed by
consistent-looking effective field theories. We use universality ideas from
string theory to suggest that this is not the case, and that the landscape is
surrounded by an even more vast swampland of consistent-looking semiclassical
effective field theories, which are actually inconsistent. Identification of
the boundary of the landscape is a central question which is at the heart of
the meaning of universality properties of consistent quantum gravitational
theories. We propose certain finiteness criteria as one relevant factor in
identifying this boundary (based on talks given at the Einstein Symposium in
Alexandria, at the 2005 Simons Workshop in Mathematics and Physics, and the
talk to have been presented at Strings 2005).
