By Jean Tancous This classic book on leather technology has been comp- letely updated. The author states in her preface: ''The purpose of this book is two-fold. It is designed primarily to summarize and to appraise our present knowledge of the causes and means of identifying defects of skin, hide and leather. Its other purpose is to serve as a continuing effort to reduce and eliminate such losses.'' The book covers defects in leather caused by: natural characteri- stics, diseases, parasites, and mechanical damage; as well as damage during killing, curing, storage, shipping, and in the tanning process. (360 photographs, 363 pages)