  The CMS Detector consists of a large volume silicon tracker immersed in a
high four Tesla magnetic field, together with a high resolution/granularity
electromagnetic calorimeter and a nearly full solid angle coverage hadronic
calorimeter. Particle flow reconstruction provides a global pp-collision event
description by exploiting the combined information across all CMS
sub-detectors, optimizing the reconstruction and the identification of each
particle (photons, electrons, muons, unstable neutral hadrons, charged hadrons
and neutral hadrons) in an event. This summary introduces the CMS particle flow
algorithm, discusses the challenges associated with the LHC environment, and
presents some first example results in the context of hadronic decays of taus
as well as missing transverse energy.
