Dehydration continues to be an active area for R&D in view of the importance of this ubiquitous unit operation as the most cost-effective means of preservation and production of products of biological origin. With few exceptions, quality and hence the market value of the dried product is governed by drying operation. The selection of appropriate drying equipment and the operating conditions are therefore of paramount interest. The coverage ranges from drying fundamentals and modeling (e.g. psychrometry, role of glass transitions in drying, diffusion model of falling rate period, freeze drying, vacuum drying etc.), to drying practices in wood, biomass, alfalfa, cocoa etc. processing. It also covers new drying technologies such as, superheated steam drying and heat pump drying in inert atmosphere, that have already been accepted in the industry.