In the present volume-as in previous editions-the intention of the author is to survey comprehensively all medicinal drugs commonly in use together with their pharmaceutical preparations. The last five years has seen a very rapid advance in the field of pharma- ceutical analysis and the need for revision of the previous edition has become evident. Further, the claims for incorporation of all methods used in the examination of drugs-chemical, physical, microbiological and biological-cannot be denied any longer since each type of determination is sometimes necessary for the adequate control of medicinal preparations.. The author's practice in this book has always been to select from ex- perience those methods likely to prove most serviceable rather than pro- duce a compendium of all published methods. Because of the rapid increase in the techniques available for pharmaceutical analysis, the need for specialisation has grown and the author has realised the impractic- ability of keeping in touch with all the practical details which are so valuable to the analyst. To overcome this difficulty and to enhance the value of the book, he has obtained the collaboration of specialist colleagues.