  Centaurus A (NGC5128) is a fantastic object, ideal for investigating the
characteristics and the role of the gas in an early-type galaxy in the presence
of a radio-loud active nucleus. The different phases of the gas - hot (X-ray),
warm (ionised) and cold (HI and molecular) - are all detected in this object
and can be studied, due to its proximity, at very high spatial resolution. This
richness makes Centaurus A truly unique. Spatially, these gas structures span
from the pc to the tens of kpc scale. Thus, they allow us to trace very
different phenomena, from the formation and evolution of the host galaxy, to
the interplay between nuclear activity and ISM and the feeding mechanism of the
central black hole. A lot of work has been done to study and understand the
characteristics of the gas in this complex object and here I summarise what has
been achieved so far.
