The next generation of linear colliders

General introduction to the physics and technologies of linear e+e- colliders. An attempt will be made to compare the merits of the different technologies of currently proposed colliders with centre of mass energies in the 0.5-1.0 TeV range. Problems and technologies for multi-TeV Colliders will be discussed and the relative advantages of proton-proton, y y and m+ m- colliders will be compared. 1, Focus, disruption and beamstrahlung; 2, Production and dampin;. 3, Acceleration; 4, RF power production; 5, Emittance preservation; 6, Costs, comparisons and conclusions.