  We present a comprehensive review of the current state of fracture phenomena
in transient networks, a wide class of viscoelastic fluids. We will first
define what is a fracture in a complex fluid, and recall the main structural
and rheological properties of transient networks. Secondly, we review
experimental reports on fractures of transient networks in several
configurations: shear-induced fractures, fractures in Hele-Shaw cells and
fracture in extensional geometries (filament stretching rheometry and pendant
drop experiments), including fracture propagation. The tentative extension of
the concepts of brittleness and ductility to the fracture mechanisms in
transient networks is also discussed. Finally, the different and apparently
contradictory theoretical approaches developed to interpret fracture nucleation
will be addressed and confronted to experimental results. Rationalized criteria
to discriminate the relevance of these different models will be proposed.
