  In a wide class of holographic models, like the one proposed by Sakai and
Sugimoto, baryons can be approximated by instantons of non-abelian gauge fields
that live on the world-volume of flavor D-branes. In the leading order, those
are just the Yang-Mills instantons, whose solutions can be obtained from the
celebrated ADHM construction. This fact can be used to study various properties
of baryons in the holographic limit. In particular, one can attempt to
construct a holographic description of the cold dense nuclear matter phase of
baryons. It can be argued that holographic baryons in such a regime are
necessarily in a solid crystalline phase. In this review we summarize the known
results on the construction and phases of crystals of the holographic baryons.
