As the subtitle indicates, the overriding intention of the authors has been to provide a practical guide to the design of electrolytic plant. We wanted to show that the procedures for the design and optimization of such a plant are essentially simple and can be performed by readers comparatively new to the electrochemical field. It was important to realize that electrochemical engineering should not be confused with applied electrochemistry but had to be based on the principles of chemical engineering. For this reason, reference is often made to standard chemical engineering texts. Since this is a practical guide rather than a textbook, we have included a large number of worked examples on the principle that a good worked example is worth many paragraphs of text. In some examples we have quoted costs, e.g., of chemicals, plant or services. These costs are merely illustrative; current values will have to be obtained from manufacturers or journals. If this is not possible, approximate methods are available for updating costs to present-day values (see Refs. 1 and 3, Chapter 6).

This book has been planned and written by Dr. Hine with his knowledge and experience in electrochemical science and engineering for over thirty years since he joined with me at Kyoto University in 1948. This book is unique and is useful for engineers as well as scientists who are going to work in any interdisciplinary field connected with elec trochemistry. Science is sure to clarify the truth of nature as well as bring prosperity and an improvement to the welfare of human beings. The origin of the word "science" is the same as of "conscience," which means the truth of our heart. When we consider a scientific and technological subject, first we classify it into the components and/or factors involved, and then we clarify them individually. Second, we combine them to grasp the whole meaning and feature of the subject under discussion. Computers may help us greatly, but how to establish the software that will be most desirable for our purposes is of great importance. We need to make these efforts ourselves, and not decorate with borrowed plumes. With this concept in mind, this book is attractive because the author describes the basic science in electrochemistry and practice, and discusses the electrochemical engineering applications as a combination of science and technology.

The objective of this second edition remains the discussion of the many diverse roles of electrochemical technology in industry. Throughout the book, the intention is to emphasize that the applications, though extremely diverse, all are on the same principles of electrochemistry and electrochemical engineer based ing. Those familiar with the first edition will note a significant increase in the number of pages. The most obvious addition is the separate chapter on electrochemical sensors but, in fact, all chapters have been reviewed thoroughly and many have been altered substantially. These changes to the book partly reflect the different view of a second author as well as comments from students and friends. Also, they arise inevitably from the vitality and strength of electrochemical technology; in addition to important improvements in tech nology, new electrolytic processes and electrochemical devices continue to be reported. In the preface to the first edition it was stated: . . . the future for electrochemical technology is bright and there is a general expectation that new applications of electrochemistry will become economic as the world responds to the challenge of more expensive energy, of the need to develop new materials and to exploit different chemical feedstocks and of the necessity to protect the environment. The preparation of this second edition, seven years after these words were written, provided an occasion to review the progress of industrial electro chemistry.