Sections dealing with fuzzy functions and fuzzy random functions are certain to be of special interest. The reader is expected to have a solid understanding of the knowledge gained in a basic university mathematics course, including stochastic elements. Specifying uncertainty in any particular case can often be challenging. For this reason, chapters 3 and 4 are dedicated solely to this issue. The derivation of fuzzy variables for representing informal and lexical uncertainty reflects the subjective assessment of objective conditions in the form of a membership function. Techniques for modeling fuzzy random variables are presented for data that exhibit both stochastic and non-stochastic properties. The application of fuzzy randomness is demonstrated in three fields of civil engineering and computational mechanics: structural analysis, safety assessment, and design.