The development of information processing systems requires models,
calculi, and theories for the analysis of computations. It is well
understood by now that more complex software systems cannot and should
not be constructed in one step. A careful, systematic, and disciplined
structuring of the development process is most adequate. It should start
from basic requirement specifications in which aU the relevant details
of the problem to be solved are formalized. The envisaged solution
should be developed step by step by adding more and more details and
giving evidence-in the best case by formal proof-to show the correctness
of the developed steps. The development ends if a description of a
solution is obtained that has aU the required properties. The Summer
School in Marktoberdorf 1992 showed significant approaches in this area
to refinement calculi, to models of computation, and as a special issue
to the treatment of reactive timed systems. Like in the many summer
schools before, the success of the 1992 Summer School was not only due
to the excellent lectures, but even more due to the brilliant students
taking part in the discussions at the summer school, the exchange of
different views, and the recognition of the similarity of a number of
different view points. These were some of the most important
contributions of the summer school. fu the following the proceedings of
the summer school are collected. They show the maturity of the field in
an impressive way.