  In this contribution the symmetry properties of the interacting boson model
of Arima and Iachello are reviewed. While the concept of a dynamical symmetry
is by now a familiar one, this is not necessarily so for the extended notions
of partial dynamical symmetry and quasi dynamical symmetry, which can be
beautifully illustrated in the context of the interacting boson model. The main
conclusion of the analysis is that dynamical symmetries are scarce while their
partial and quasi extensions are ubiquitous.
