Physics with the TESLA linear collider

High energy epsilon (+)epsilon (-) colliders have been essential tools in the search for the fundamental constituents of matter and their interactions and have thus made important contributions to the validation of the Standard Model. It is therefore desirable to extend the centre-of-mass energy of future colliders from that presently obtained at LEP (roughly 200 GeV) into the LHC energy, with luminosities well above 10(34) cm(-2)s(-1). Such high energies and luminosities can only be reached using electron-positron linear colliders. The physics potential of a high energy epsilon (+)epsilon (-) collider and the success of the Stanford Linear Collider have led to a world wide coordinated effort to construct such a facility. Detailed design work as well as the construction of large test facilities is underway at most major particle physics laboratories. In this article: the physics potential and design of TESLA, a collider based on low frequency superconduction rf cavities, will be discussed.