  In this introduction to the Third Congress of Vienna on AGB stars I first try
to highlight why it is so hard to cope with the AGB evolutionary phase. This
phase is indeed dominated by three main physical processes concerning bulk
motions of matter inside/around stars, namely envelope convection, mixing and
mass loss. They are inextricably interlaced with each other in a circular
sequence of reactions and counter-reactions which has so far undermined our
attempts at calibrating such processes one independent of the other. The second
part of this introduction is focused on Globular Clusters, illustrating how
they came to be a {\it new frontier} for the AGB evolution and a new
opportunity to understand it.
