Dew droplets scatter the light of the early morning sun like thousands of diamonds. Billions of passing rain droplets, refracting and internally reflecting the sunlight, form the rainbow, stretching across the sky and competing in its magnificence with the red fire ball of the sunset. Droplets are encountered not only in nature but also in a wide range of engineering applications, such as spray combustion, spray drying, spray cooling, etc., etc. The related areas span automotive, aerospace, metallurgy, material, chemicals, pharmaceuticals, paper, food processing, agriculture, meteorology, and power generation. It was these applications that stimulated the fundamental research and development of the technologies associated with discrete droplets. In the past century, droplet-related phenomena have been a subject of considerable scientific interest and practical importance. Inrecent years, strong research efforts have led to significant strides in theoretical and experimental studies of droplet processes. The drastic developments in high speed, large memory, parallel processing computer systems and advanced computational and measurement techniques have enabled the direct numerical modeling and on-line, in situ measurements of certain droplet properties, and thus largely advanced the design and optimization of droplet processes. These advances have significantly improved our fundamental understanding of the phenomena and processes associated with discrete droplets in general. It is therefore desirable to review these results in a timely manner. This book presents an updated, systematic review of the recent advances in fundamental science and engineering applications of discrete droplet processes. The objective of this book is to familiarize the reader with the scientific and engineering aspects of discrete droplet processes, and to provide experienced researchers, scientists and engineers in academic and industry communities with the latest developments in this field. The scope of this book encompasses the fundamental science and engineering applications of discrete droplet processes of both normal liquids (i.e., aqueous or oil-based liquids) and melts (i.e., molten metals, alloys, ceramics or polymers). It starts with a systematic survey of various processes and techniques for droplet generation, along with their applications and associated materials systems. It is followed by a through description of the fundamental phenomena and principles involved in droplet processes, with emphasis on the mechanisms of droplet formation and deformation in vario us processes. The empirical and analytical correlations, theoretical calculations and numerical modeling of droplet properties are outlined and some approaches to intelligent process control are presented along with discussions of recent developments. There have been books on droplet-related processes. However, the present book is probably the first one that encompasses the fundamental phenomena, principles and processes of discrete droplets of both normal liquids and melts. The author has attempted to correlate many diverse mechanisms and effects in a single and common framework in an effort to provide the reader with a new perspective of the identical basic physics and the inherent relationship between normal liquid and melt droplet processes. Another distinct and unique feature of this book is the comprehensive review of the empirical correlations, analytical and numerical models and com puter simulations of droplet processes. These not only provide practical and handy approaches for engineering calculations, analyses and designs, but also form a useful basis for future in-depth research.Therefore, the present book covers the fundamental aspects of engineering applications and scientific research in the area.