Will cosmologists look back on 1998 as a year that rivals 1964 in importance? I think it is quite possible. In any case, the flood of data that is coming will make the next twenty years in cosmology very exciting. It could be that my younger theoretical colleagues will get their wish - inflation + cold dark matter is falsified and it's back to the drawing board. Or, it may be that it is roughly correct, but the real story is richer and even more interesting. This happened in particle physics. The quark model of the 1960s was based upon an approximate SU(3) global flavor symmetry, which shed no light on the dynamics of how quarks are held together. The standard model of particle physics that emerged and which provides a fundamental description of physics at energies less than a few hundred GeV, is based upon the SU(3) color gauge theory of quarks and gluons (QCD) and the SU(2) U(1) gauge theory of the electroweak interactions. The difference between global and local SU(3) symmetry was profound.
Even if Inflation + Cold Dark Matter does pass the series of stringent tests that will confront it in the next decade, there will be questions to address and issues to work out. Exactly how does inflation work and fit into the scheme of the unification of the forces and particles? Does the quantum gravity era of cosmology, which occurs before inflation, leave a detectable imprint on the Universe? What is the topology of the Universe and are there additional spatial dimensions? Precisely how did the excess of matter over antimatter develop? What happened before inflation? What does Inflation + Cold Dark Matter teach us about the unification of the forces and particles of Nature? We live in exciting times!