Power Corrections at LEP

The size of non-perturbative corrections to event shape observables is predicted to fall like powers of the inverse centre of mass energy. These power corrections are investigated for different observables from $e^{+}{e}^{-}$-annihilation measured at LEP as well as previous experiments. The obtained corrections are compared to other approaches and theoretical predictions. Measurements of ${\alpha }_s$ using power corrections are compared to conventional methods.