  Alfven waves are considered to be viable transporters of the non-thermal
energy required to heat the Sun's quiescent atmosphere. An abundance of recent
observations, from state-of-the-art facilities, have reported the existence of
Alfven waves in a range of chromospheric and coronal structures. Here, we
review the progress made in disentangling the characteristics of transverse
kink and torsional linear magnetohydrodynamic (MHD) waves. We outline the
simple, yet powerful theory describing their basic properties in (non-)uniform
magnetic structures, which closely resemble the building blocks of the real
solar atmosphere.
