The book intends to discuss the basic ideas, underlying principles, mathematical formulations, analysis and applications of the different combinatorial problems under uncertainty and attempts to provide solution/s for the same. Uncertainty influences the behaviour of the market to a great extent. Global pandemics and calamities are another factor which affects and augments unpredictability in the market. The intent of this edited book is to develop mathematical structure for different aspects of allocation problem depicting real life scenarios. The novel methods which are incorporated in practical scenarios under uncertain circumstances include STAR heuristic approach, Matrix geometric method, Ranking function, Pythagorean fuzzy numbers, to name a few. Distinct problems which are considered in this book under uncertainty includes, scheduling, cyclic bottleneck assignment problem, bilevel transportation problem, multi-index transportation problem, retrial queuing, uncertain matrix games, optimal production evaluation of cotton in different soil and water conditions, healthcare sector, intuitionistic fuzzy quadratic programming problem, multi-objective optimization problem. The book may serve as a valuable reference for the researchers working in the domain of optimization for solving combinatorial problems under uncertainty. The contributions of the book may further help to explore new avenues leading toward multidisciplinary research discussions.