Drying has a wide range of applications in many industries, including food and beverage, chemical, medicine, textile, mineral processes, sludge drying, and many others. Drying is commonly used as the final step of production to ensure minimum loss of product quality and to increase the shelf life of final products. Various operating parameters affect the overall drying performance, such as drying temperature profile, feed size, moisture content, and so on. The main disadvantages of the drying process are its high energy requirements and damage to final product quality. Hybrid technologies, for example, ultrasound-assisted and microwave-assisted drying, are being developed to overcome the limitations of current drying processes. Both methods have been shown to exhibit higher efficiency and less impact on the product quality. Chapter 9 discusses the fundamentals of drying, its benefits and drawbacks, and various drying technologies.