Galaxy classification is one of those enjoyable aspects of galaxy research that few of us consider ourselves specialists in. Most of us obtain the morphological information we require from the large catalogues or lists provided by a few respected "morphologists", and rarely attempt to improve on those types by re-inspecting the galaxies ourselves or by carrying out an imaging survey. Though we may on occasion question a catalogue type in individual cases, especially if better image material becomes available, published morphological types provide an important starting point for most extragalactic research. This is as true today as it was 66 years ago when Hubble published his famous classification system. There can be little doubt now that nature and nurture play a role in determining the morphology of galaxies. The main questions are to what degree have each of these processes influenced present-day morphology, and how do we recognize these influences. Morphology alone cannot answer these questions, so a confrontation between theory and observation is essential. It is thus fitting to begin this conference with a review of the morphological classification of galaxies, since this provides the background for the nature vs. nurture controversy. Due to space limitations, the discussions are necessarily brief.