  SPIRIT is an expert system shell for probabilistic knowledge bases. Knowledge
acquisition is performed by processing facts and rules on discrete variables in
a rich syntax. The shell generates a probability distribution which respects
all acquired facts and rules and which maximizes entropy. The user-friendly
devices of SPIRIT to define variables, formulate rules and create the knowledge
base are revealed in detail. Inductive learning is possible. Medium sized
applications show the power of the system.
