Effective Field Theory for Inflation
  This is a version of the author's Ph.D. thesis. The methods of effective
field theory are used to study generic theories of inflation with a single
inflaton field and to perform a general analysis of the associated
non-Gaussianities. We investigate the amplitudes and shapes of the various
three and four-point correlators which are generated by different classes of
single-field inflationary models. Besides the well-known results for the so
called P(X,\phi) model and the ghost inflationary theories, which we recover,
we point out that extrinsic curvature-generated interactions may give rise to
large non-Gaussianities with distinctive features in the form of specific
shape-functions (e.g. flat, orthogonal etc..) for the correlators.
