The aim of the INTERNATIONAL YEARBOOKS OF NEPHROLOGY is to publish every year a volume to keep nephrologists up to date on all the rapidly changing areas of nephrology. Each volume will be published by the end of each calendar year which corresponds with the annual meeting of the American Society of Nephrology. Each issue of the INTERNATIONAL YEARBOOKS OF NEPHROLOGY will be divided into sections; each section will have different primary focus every year, depending upon what area is of greatest interest at the time. In other words, each annual volume will deal with what is truly current in nephrology. All the authors appointed for the chapters of the INTERNATIONAL YEARBOOKS OF NEPHROLOGY are known experts in the field who will give an objective review of the topic up-dating the readers on the world-wide literature. A crucial point for the success of the INTERNATIONAL YEARBOOKS OF NEPHROLOGY is the list of the references at the end of each chapter. We have asked all authors to provide a complete, accurate and up-to-date list of important references. In order to guarantee the most up-to-date yearbook, very rapid production is mandatory. Rapid publication can be obtained only with camera-ready manuscripts for direct photo-offset reproduction. Thus we have agreed to use photo-offset printing for the series. For the first issue of the series, the INTERNATIONAL YEARBOOK OF NEPHROLOGY 1989, the Editorial Board has focused attention on the latest and most important scientific and clinical advances in nephrology.

The 1991 International Yearbook of Nephrology is the third in a sueeessful .eries whieh has, as its principal aim, thc presentation of a eomprehensive list of topfes of the greatest current relevanee to elinieal nephrologists. We believe that, by following the subjeets eovered by the Yearbook in the broad field of nephrology, the praetieing nephrologist and nephrologist-in-training ean stay abreast of a number of rapidly advaneing fields. To improve the quality of the Yearbook, we have appointed an Editorial Board to provfde suggestions for topies and authors. Thus, we have invited 58 outstanding nephrologists from around the world (the list of them is included in this issue of the Yearbook) to identify annually potential topies for the Yearbook. The reply was exeel lent and the contribution quite outstanding. Thus, for the 1992 Yearbook, we reeeived more than 150 suggestions. A number of them will be included in the next issue if they continue to be viewed as eurrent and important. We also invite readers to suggest topies for upeoming issues of the Yearbook. The present issue, the 1991 Yearbook, represents an improvement over previous volumes. We expeet this trend to be maintained in future years. As in previous issues, all ehapters provide a eomplete, aeeurate and up-to-date list of important references. We are grateful to all the authors for their exeellent eontributions and for having fulfilled the deadline in forwarding their manuseript. Our special thanks to Kluwer Aeademie Publishers for the timely publieation of this volume."

The 1991 International Yearbook of Nephrology is the third in a sueeessful .eries whieh has, as its principal aim, thc presentation of a eomprehensive list of topfes of the greatest current relevanee to elinieal nephrologists. We believe that, by following the subjeets eovered by the Yearbook in the broad field of nephrology, the praetieing nephrologist and nephrologist-in-training ean stay abreast of a number of rapidly advaneing fields. To improve the quality of the Yearbook, we have appointed an Editorial Board to provfde suggestions for topies and authors. Thus, we have invited 58 outstanding nephrologists from around the world (the list of them is included in this issue of the Yearbook) to identify annually potential topies for the Yearbook. The reply was exeel lent and the contribution quite outstanding. Thus, for the 1992 Yearbook, we reeeived more than 150 suggestions. A number of them will be included in the next issue if they continue to be viewed as eurrent and important. We also invite readers to suggest topies for upeoming issues of the Yearbook. The present issue, the 1991 Yearbook, represents an improvement over previous volumes. We expeet this trend to be maintained in future years. As in previous issues, all ehapters provide a eomplete, aeeurate and up-to-date list of important references. We are grateful to all the authors for their exeellent eontributions and for having fulfilled the deadline in forwarding their manuseript. Our special thanks to Kluwer Aeademie Publishers for the timely publieation of this volume."

The aim of the INTERNATIONAL YEARBOOKS OF NEPHROLOGY is to publish every year a volume to keep nephrologists up to date on all the rapidly changing areas of nephrology. Each volume will be published by the end of each calendar year which corresponds with the annual meeting of the American Society of Nephrology. Each issue of the INTERNATIONAL YEARBOOKS OF NEPHROLOGY will be divided into sections; each section will have different primary focus every year, depending upon what area is of greatest interest at the time. In other words, each annual volume will deal with what is truly current in nephrology. All the authors appointed for the chapters of the INTERNATIONAL YEARBOOKS OF NEPHROLOGY are known experts in the field who will give an objective review of the topic up-dating the readers on the world-wide literature. A crucial point for the success of the INTERNATIONAL YEARBOOKS OF NEPHROLOGY is the list of the references at the end of each chapter. We have asked all authors to provide a complete, accurate and up-to-date list of important references. In order to guarantee the most up-to-date yearbook, very rapid production is mandatory. Rapid publication can be obtained only with camera-ready manuscripts for direct photo-offset reproduction. Thus we have agreed to use photo-offset printing for the series. For the first issue of the series, the INTERNATIONAL YEARBOOK OF NEPHROLOGY 1989, the Editorial Board has focused attention on the latest and most important scientific and clinical advances in nephrology.

The 1992 International Yearbook of Nephrology is the 4th in a successful series of yearly books updating practising nephrologists and nephrologists-in-training on rapidly changing areas of nephrology. We were encouraged to proceed in our editorial venture by reviews of the previous issues which have appeared in various Nephrology Journals. These reviews have pointed to the successful use of the International Editorial Board, the broad range of topics of current interest which have been covered and the comprehensive and practical nature of the reviews. The principal aim of the Yearbook remains to provide reviews which are more current than those which appear in Nephrology textbooks and which can be in the hands of the readers a few months after the authors have completed the manuscripts. The appointed authors are always experts in the field, who are asked to give an objective review of the topic, up-dating the readers on the world-wide literature and providing them with a complete, accurate and up-ta-date list of important recent references. We have decided to maintain the successful format of the first three issues. Thus, the volume will continue to be divided into sections; each section will continue to have a different primary focus every year, depending upon what is of greatest interest at the time.

Nephrology, initially born as a small branch of medicine, has, in the last few decades, become an extraordinary large field of medicine. The recent development of renal medicine is mirrored by the numerous nephrological journals published, a natural consequence of the increasing number of basic and clinical research studies performed continuously all over the world. Undoubtedly the progress which has occurred in the different, specific fields of renal medicine has given rise to subspecialities which range from renal physiology and pathology to hemo- and peritoneal dialysis and renal transplantation. Even the diagnostic methodology in nephrology, very useful in the clinical practice, has become a speciality within the speciality. Thus, the problem for clinical nephrologists, as well as for internists, is to remain continuously up-dated in all fields of nephrology. Nephrology textbooks are published continuously and in great number. However, the time required for having authors appointed, chapters completed, manuscript edited, galley proofs corrected and the whole book printed makes many textbooks already out of date when they go on sale and their half lives are very short. On the other hand, nephrological journals are so many and the articles so numerous and detailed, that it is often impossible to rely on them for up-dating practicing clinicians.