  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.
