As was pointed out in the Preface to the First Edition, it has been found necessary to divide the present work into two volumes, of which this volume is the second. It will be found to cover the necessary ground dealing with the isolated constituents of essential oils and the principal synthetic perfume materials. The analysis of essential oils is also dealt with in this volume, and a short supplementary chapter is added with a view to bringing it as nearly up to date as possible.<br><br>I have to acknowledge my indebtedness to the Editor of the Perfumery and Essential Oil Record for permission to reproduce much useful information, and also to my friend M. Charabot, whose valuable work largely forms the basis of Chapter I, of the present volume. I am indebted to Mr. C. T. Bennett, B.Sc., F.I.C., for revising the section on the Determination of Alcohols and Esters, and to Mr. W. S. Simmons, B.Sc., F.C.S., for revising the section dealing with the Determination of Aldehydes and Ketones. I have to acknowledge my thanks to Dr. Kremers for much friendly criticism, and for supplying me with reprints of several papers issued from the Chemical Department of the University of Wisconsin, but which previously escaped my notice.