A brief review of 'little string theories'

This is a brief review of the current state of knowledge on 'little string theories', which are non-gravitational theories having several string-like properties. We focus on the six-dimensional maximally supersymmetric 'littl e string theories' and describe their definition, some of their simple prop erties, the motivations for studying them, the discrete lightcone quantizat ion and holographic constructions of these theories and their behaviour at finite energy density.