Various aspects of the physics made at LEP 1 and LEP 2 (precision measurements and searches for new physics will be discussed, from
the fundamental motivations to the publication of the results. The techniques and tools developed and applied to reach the a priori goals
of LEP (beam energy measurement, luminosity determination, event selection,...) will be described with a few meaningful examples. The
high level techniques & bright ideas which allowed LEP to exceed by a large amount its design performance, and the consequences
outcome will also be presented.