This book contains two sets of notes prepared for the Advanced Course on
R- sey Methods in Analysis given at the Centre de Recerca Matem` atica
in January 2004, as part of its year-long research programme on Set
Theory and its Appli- tions. The common goal of the two sets of notes is
to help young mathematicians enter a very active area of research lying
on the borderline between analysis and combinatorics. The solution of
the distortion problem for the Hilbert space, the unconditional basic
sequence problem for Banach spaces, and the Banach ho- geneous space
problem are samples of the most important recent advances in this area,
and our two sets of notes will give some account of this. But our main
goal was to try to expose the general principles and methods that lie
hidden behind and are most likely useful for further developments. The
goal of the ?rst set of notes is to describe a general method of
building norms with desired properties, a method that is clearly
relevant when testing any sort of intuition about the
in?nite-dimensional geometry of Banach spaces. The goal of the second
set of notes is to expose Ramsey-theoretic methods relevant for
describing the rough structure present in this sort of geometry. We
would like to thank the coordinator of the Advanced Course, Joan Ba-
ria, and the director of the CRM, Manuel Castellet, for giving us this
challenging but rewarding opportunity. Part A SaturatedandConditional
StructuresinBanachSpaces SpirosA.