Basic Constituents of Matter and their Interactions - A Progress Report

Our concept of the basic constituents of matter has undergone two revolutionary changes – from atoms to proton & neutron and then onto quarks & leptons. Indeed all these quarks and leptons have been seen by now along with the carriers of their interactions, the gauge bosons. But the story is not complete yet. A consistent theory of mass requires the presence of Higgs bosons along with SUSY particles, which are yet to be seen. This is a turn of the century account of what has been achieved so far and what lies ahead.