  Over the last 40 years, multi-frequency observations, coupled with advances
in theoretical modelling, have led to a much fuller understanding of the nova
phenomenon. Here I give a brief review of the current state of knowledge of
Classical and Recurrent Novae including their central systems; the causes and
consequences of their outbursts; sub-types, and possible relationships to Type
Ia Supernovae. Particular attention is paid to the Recurrent Nova RS Ophiuchi
as it shows a wealth of phenomena associated with its 2006 outburst. Finally,
some open questions and avenues for future work are summarised.
