Quantum algebras are a mathematical tool which provides us with a class of
symmetries wider than that of Lie algebras, which are contained in the form
er as a special case. After a self-contained introduction to the necessary
mathematical tools (q-numbers, q-analysis, q-oscillators, q-algebras), the
su(q)(2) rotator model and its extensions, the construction of deformed exa
ctly soluble models (u(3)superset of so(3) model, Interacting Boson Model,
Moszkowski model), the 3-dimensional q-deformed harmonic oscillator and its
relation to the nuclear shell model, the use of deformed bosons in the des
cription of pairing correlations, and the symmetries of the anisotropic qua
ntum harmonic oscillator with rational ratios of frequencies, which underly
the structure of superdeformed and hyperdeformed nuclei, are discussed in
some detail. A brief description of similar applications to the structure o
f molecules and of atomic clusters, as well as an outlook are also given.