The Strong Coupling: Measurements and Running

Abstract

Measurements of \alpha_s from event shapes in e^{+} e^{-} annihilation are discussed including recent determinations using experimentally optimized scales, studies of theoretically motivated scale setting prescriptions, and recently observed problems with predictions in Next to Leading Logarithmic Approximation. Other recent precision measurements of \alpha_s are briefly discussed. The relevance of power terms for the energy evolution of event shape means and distributions is demonstrated. Finally a summary on the current results on \alpha_s(M_Z) and its running is given.