This book have new developments and techniques in clinical biochemistry have continued to appear at a rate which shows no sign of falling and the pressure on those in charge of routine laboratories has continued to increase. As a result the task of revision has proved to be a heavier one than formerly the more so as this has been more evenly spread a number of sections which were left unchanged in previous revisions having been brought more into line with current views. A second introductory chapter has been inserted which it is hoped will help to give a clearer under- standing of some separative procedures; this also includes a section on the AutoAnalyzer and some automatic measuring instruments. Chapters which have been given considerable rewriting include those on proteins enzymes acid-base regulation hemoglobin and related compounds and hormones and among shorter sections those dealing with quality control the normal range hypoglycemia amino-acid disorders flamephotometry pyridoxine and folic acid.