Discovery of neutral current (NC) more than 25 years ago laid the foundation of the standard model (SM). Ever since then the NC has been tested to a high accuracy. I briefly review the SM and the NC interactions, and some important historical experiments that established the NC.
Collider experiments in the 90's continue to test the NC. I summarize a global set of lepton-quark NC experiments, including the NC deep-inelastic scattering at HERA, hadronic production at LEPII, Drell-yan production at the Tevatron, atomic parity violation, electron-nucleon and neutrino-nucleon scattering. A few popular models beyond the SM that would cause deviations in NC are described. A model independent approach is employed to obtain the constraints on the new physics. I shall also estimate the sensitivity reach in the future experiments at RunII and at the LHC.