WEIN '98 focussed on searches for physics beyond the Standard Model of elementary particles at low and medium energies, including theoretical studies in these areas. In addition. selected topics in the physics of the Standard Model, searches for new physics at high energy facilities, and topics in nuclear and particle astrophysics were discussed. The conference was mainly composed of plenary talks reviewing the present status of the field. The proceedings include written versions of these plenary talks plus several invited talks given at the parallel sessions covering specific topics that could not he included in the plenary sessions.