Models: The Art of Understanding is primarily about the use of Microsoft Excel as a powerful tool in the hands of one who needs to understand how the pieces of a wide range of processes in different sectors fit together-in other words, the meaning of numbers. These processes include those in the fields of maritime transportation, manufacturing, statistical process control, natural resources, healthcare, retail, insurance, blockchain, oil and gas production, airport management, civil engineering, energy, education, military, and the public sector. It begins with an introduction to the importance of models in budgeting, planning, and decision analysis. This is followed by a discussion of how Excel can be used to develop such models. This material includes a number of examples of how different processes can be modelled. Models is not really a textbook or a memoir or even an encyclopedia but a blend of the three with the intention of introducing the reader to the whole adventurous world of dumping the quantitative pieces of a puzzle on the table and proceeding, piece by piece, to fit them together until a picture of the whole emerges-and finally using the end product to coordinate the understanding and activities of a management team to reach the highest possible level of productivity and success. It can be engaged on a number of different levels by a wide range of interested parties. The one common denominator is a profound desire to understand.