  Spin-orbit coupled materials have attracted revived prominent research
interest as of late, especially due their direct connection with topological
notions. Arguably, a hallmark of this pursuit is formed by the concept of the
topological band insulator (TBI). In these incompressible systems band
inversions, often driven by strong spin-orbit coupling, result in a state that
is topologically distinct from the usual insulator as long as time reversal
symmetry is maintained. More generally, topological states that arise by virtue
of a protecting symmetry have resulted in a flourishing research field on both
the experimental as well as theoretical side of the condensed matter agenda. As
a prime signature topological band insulators can exhibit protected spin
filtered edge states, whose time reversal invariant partner is spatially
separated on the other edge. While these edge states have resultantly been
identified with many exotic physical phenomena, we here wish to provide a
perspective on the equally rich, although far less explored, aspects of the
bulk. That is, we will focus on the role of lattice defects, dislocations in
particular, and their relation with the topological nature of the bulk.
