At the last IAEA Technical Committee Meeting at Gut Ising in October 1988, JET reported on the generation of confinement improved PEP (Pellet Enhanced Plasmas) modes by early injection of 4 mm deuterium pellets and subsequent central heating with about 8-10MW of I on Cyclotron Radio frequency Heating (ICRH) or combined ICRH/Neutral Beam Injection (NBI) Heating in otherwise L-mode type 3MA discharges. Since then, JET has expanded these pulses to higher plasma currents, higher additional heating power levels, employment of larger pellet size and particularly has combined the PEP modes with H-mode plasmas (1990/91) obtaining transiently plasma performances approaching those of the best competing scenarios. Essentially this paper reports is an excerpt from [3] expanded by more recent experiments and findings; it does not intend to give a full review of the JET pellet experiments nor even of the immense variety of the PEP-mode phenomena. The evaluation of the pellet data is ongoing and has allowed some insight into the reason for the PEP confinement and its transient nature. The JET pellet data base contains a good 200 shots with pellet injection of which about 120 show clear PEP indications; its review has revealed some trends which are now being followed up.