Overview of theoretical problems related to LEP2

After 12 years of glorious data taking LEP has been shut down. During the past two years an incredible effort has been devoted to get more accurate predictions and estimates of the related theoretical uncertainties. Many of the theoretical questions driven by LEP are also relevant at the LC, where predictions will be needed with even higher accuracy. This is particularly true for 4-fermion Physics. In this contribution, I review some of the most important theoretical achievements at LEP in understanding W and Z pair production, 4-fermion + 1 visible photon signatures and in solving problems related with gauge invariance. Issues on single W Physics are covered elsewhere. Part of the presented work is in progress, the final LEP2 analysis still being under way.