Until a few years ago, most transient transport studies observed prima
rily diffusive plasma transport responses to fast, localized perturbat
ions. Recently, several experiments have, in addition, observed 'non-l
ocal' electron heat responses. Most remarkably, in 'cold-pulse' experi
ments the abrupt edge cooling via radiative processes can induce both
a diffusive cooling response moving in from the edge and, simultaneous
ly, a rising electron temperature in the central core of tokamak plasm
as-an opposite response even before the diffusive cooling from the edg
e reaches the centre! These and other non-local electron heat transpor
t conundra from recent experiments are reviewed. The models and physic
al processes advanced to explain these puzzling phenomena are also dis
cussed. The importance of resolving this transport enigma is emphasize
d.