An interdisciplinary book for knowledge workers in business, finance, management and socio-economic sciences. The book provides a guide to and techniques for forecasting, decision making, conclusions and evaluations in an environment involving uncertainty, vagueness and impression. Traditional modelling techniques do not capture the nature of complex systems especially when humans are involved. Fuzzy logic provides effective tools for dealing with such systems. Emphasis is on applications presented in case studies including time forecasting for project management, new product pricing, client financial risk tolerance policy, deviation and potential problem analysis, inventory control model, and stock market strategy.