  Spinor Bose gases form a family of quantum fluids manifesting both magnetic
order and superfluidity. This article reviews experimental and theoretical
progress in understanding the static and dynamic properties of these fluids.
The connection between system properties and the rotational symmetry properties
of the atomic states and their interactions are investigated. Following a
review of the experimental techniques used for characterizing spinor gases,
their mean-field and many-body ground states, both in isolation and under the
application of symmetry-breaking external fields, are discussed. These states
serve as the starting point for understanding low-energy dynamics, spin
textures and topological defects, effects of magnetic dipole interactions, and
various non-equilibrium collective spin-mixing phenomena. The paper aims to
form connections and establish coherence among the vast range of works on
spinor Bose gases, so as to point to open questions and future research
opportunities.
