Analytic approximations, perturbation theory, effective field theory
  methods and their applications
  We summarize the parallel session B4: 'Analytic approximations, perturbation
theory effective field theory methods and their applications' and the joint
session B2/B4: 'Approximate solutions to Einstein equations: Methods and
Applications', of the GR20 & Amaldi10 conference in Warsaw, July 2013. The
contributed talks reported significant advances on various areas of research in
gravity.
