  In the first section of these lectures I outline the classical framework of
the Hubble classification system. Because of space limitations I will focus on
points of controversy concerning the physical interpretation of the Hubble
sequence, showing how morphological ideas shape our understanding of galaxy
evolution. I will then present an overview of the remarkable progress made in
recent years in understanding how the local morphological composition has
transformed into that seen the distant Universe, highlighting work from the
Hubble Deep Field (HDF). Recent studies show quite clearly that the Hubble
system does not provide a useful framework for describing the appearance of
galaxies at redshifts z >1.5. I argue that as a result of this work the Hubble
system needs to be replaced by a system that is more objective, more physically
meaningful, and which is applicable across a wider range of redshifts.
