Operations Research focuses almost exclusively on mathematical optimization methods for optimal decision-making in applied business administration. The most important subfields for practice are discussed in this work. These include linear optimization, game theory, transportation problems, integer optimization, graph theory, network planning techniques, and simulation. Deliberately, the exact mathematical representation and proof of the presented methods are omitted. Instead, the user is intended to familiarize themselves with the areas of Operations Research through fully worked-out examples and many exercises with complete solutions.