All real systems in nature - physical, biological and engineering ones - can malfunction and fail due to faults in their components. Logically, the chances for malfunctions increase with the systems' complexity. The complexity of engineering systems is permanently growing due to their growing size and the degree of automation, and accordingly increasing is the danger of fail- ing and aggravating their impact for man and the environment. Therefore, in the design and operation of engineering systems, increased attention has to be paid to reliability, safety and fault tolerance. But it is...