The material in this book is derived from my books which were originally published by the Publication Division - SERS Publications - of my own defunct company. It is the first of a series of book-products to come, arising from my teaching and research experience at various tertiary institutions in Operations Research and Statistics; especially at the National University of Lesotho and the University of Botswana. The material is designed with a unique presentation tapping from my over thirty years of successful tertiary teaching and research.The approach to the development of the material emphasises the distinction between concepts and techniques on one hand and the problems solved through the techniques on the other, with three distinct features in contrast to many textbooks in Operations Research. First the epistemological framework of Operations Research as a science has been explicitly introduced and emphasised throughout the book. Second clear definitions and descriptions of for example what “a problem” and “an optimisation problem” mean in OR are introduced, underscoring data and decision making as the underpinnings of the concepts. Third in the examples emphasis is made in differentiating between the analytical frameworks and the optimisation problems solved through the frameworks.The discussion itself in the book is divided into six chapters. The first chapter introduces epistemological framework of Operations Research, whereby the philosophy of Operations Research as a science is emphasised.The second chapter discusses the structure of linear programming models, which have a wide range of applications in day-to-day decision making. The discussion includes the formulation of the models, the skills relating to which are built through well selected problems introduced systematically in order of their difficulty in relation to the formulation of the models. The distinction between the models and the optimisation problems they represent is clearly and well highlighted. The third chapter deals with the concepts and techniques for determining the solutions of linear programming models; specifically the Graphical Method.The fourth chapter deals with inventory optimisation problems and models, whereby the simple EOQ model is discussed. While the fifth chapter is on queueing optimisation problems and analytical frameworks, whereby the SP;∞;M[M;1;∞;FCFS(1)] analytical framework is the main focus. And the sixth and last chapter deals with network optimisation problems and analytical frameworks, whereby project-management analytical framework is discussed as an example of such frameworks.The target and approach is producing a book in OR that lectures to the reader, and the main topics covered in the chapters are as below:1: GENERAL NATURE OF OPERATIONS RESEARCH1.1:AN OVERVIEW ON DATA AND RELATED CONCEPTS1.2:STAGES IN THE APPLICATION OF OPERATIONS RESEARCH 1.3:MAIN CATEGORIES OF OPERATIONS RESEARCH MODELS 2: STRUCTURE OF LINEAR PROGRAMMING MODELS2.1:FORMULATION OF LINEAR PROGRAMMING MODELS2.2:CANONICAL MODELS 2.3:DUAL MODELS3: SOLUTIONS OF LINEAR PROGRAMMING MODELS3.1:THEORETICAL FRAMEWORK3.2:SOLUTION METHODS: GRAPHICAL METHOD3.3:SOLUTIONS OF CANONICAL MODELS3.4:RELATIONSHIP BETWEEN PRIMAL MODEL AND DUAL MODEL OPTIMAL SOLUTIONS4: INVENTORY OPTIMISATION PROBLEMS AND MODELS4.1:INTRODUCTION 4.2:SIMPLE ECONOMIC ORDER (EOQ) MODEL 5: QUEUEING OPTIMISATION PROBLEMS AND MODELS5.1:PRELIMINARY NOTE 5.2:QUEUEING OPTIMISATION AMETS (QUOPAMETS) 5.3:QUEUEING SYSTEMS IN QUOPAMETS 5.4:STRUCURE OF QUEUEING OPTIMISATION PROBLEMS 5.5:ANALYTICAL FRAMEWORKS FOR QUEUEING OPTIMISATION PROBLEMS5.6:SP;M[M;1] ANALYTICAL FRAMEWORKS6: NETWORK OPTIMISATION PROBLEMS AND MODELS6.1:EPISTEMOLOGICAL FORMATION OF NETWORK ANALYSIS 6.2:NETWORKS AND THEIR CHARACTERISTICS 6.3:NETWORK OPTIMISATION AMETS AND PROBLEMS 6.4:PROJECT-MANAGEMENT OPTIMISATION FRAMEWORKS