The XVI International Workshop on Condensed Matter Theories (CMT) was held in San Juan. Puerto Rico between June 1 and 5, 1992. It was attended by about 80 scientists from allover the world. The Workshop was started in 1977 by V. C. Aguilera-Navarro, in Sao Paolo, Brazil, as the Panamerican Workshop on Condensed Matter Theories, to promote the exchange of ideas and techniques of groups that normally do not interact, such as people working in the areas of Nuclear Physics and Solid state Physics, Many Body Theory, or Quantum Fluids, and Classical Statistical Mechanics, and so on. It had also the purpose of bringing together people from different regions of the globe. The next CMT Workshop was held in 1978 in Trieste, Italy, outside of America. But the next four met in the American continent: Buenos Aires, Argentina (1979), Caracas, Venezuela (1980), Mexico City, Mexico (1981), and St. Louis, Missouri (1982). At this time the scope and the participation had increased, and the name was changed to the "International" Workshop in CMT. The 1983 edition took place in Altenberg, Germany. The following CMT workshops took place in Granada, Spain (1984), San Francisco, California (1985), Argonne, Illinois (1986), Oulu, Finland (1987), Taxco, Mexico (1988), Campos do Jordao, Brazil (1989), Elba Island, Italy (1990), and Mar del Plata, Argentina (1991). There were 48 invited talks in this Workshop.