  Jamming is a ubiquitous phenomenon that appears in many soft matter systems,
including granular materials, foams, colloidal suspensions, emulsions,
polymers, and cells -- when jamming occurs, the system undergoes a transition
from flow-like to solid-like states. Conventionally, the jamming transition
occurs when the system reaches a threshold jamming density under isotropic
compression, but recent studies reveal that jamming can also be induced by
shear. Shear jamming has attracted much interest in the context of
non-equilibrium phase transitions, mechanics and rheology of amorphous
materials. Here we review the phenomenology of shear jamming and its related
physics. We first describe basic observations obtained in experiments and
simulations, and results from theories. Shear jamming is then demonstrated as a
"bridge" that connects the rheology of athermal soft spheres and thermal hard
spheres. Based on a generalized jamming phase diagram, a universal description
is provided for shear jamming in frictionless and frictional systems. We
further review the isostaticity and criticality of the shear jamming
transition, and the elasticity of shear jammed solids. The broader relevance of
shear jamming is discussed, including its relation to other phenomena such as
shear hardening, dilatancy, fragility, and discrete shear thickening.
