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Lord Todd’s all-too-common organic chemist will not find this information in Chemical Abstracts unless he knows the specific author or the specific substance where a given synthetic transformation is covered. He will find part of this information in Organic Reactions, especially if he looks for one of the better known “name reactions,” but he is unlikely to find any references since 1959. “Houben-Weyl” {Methoden der Organischen Chemie) will be of help and so will the annual volumes in Theilheimer’s Synthetic Methods of Organic Chemistry or the French series Cahiers de Svnthese Organique by Mathieu and Allais., In looking for pertinent examples, the chem will find directions applying to a wide variety of organic compounds, where comparison of different reaction conditions is often impossible because of the great structural differences of the various substrates.The reception of these chapters encouraged us to convert them into a form suitable for wide distribution, Through the very generous cooperation of Dr. Albert Bowers (Syntex, S. A., Mexico City), Dr. John A. Hogg (The Upjohn Company, Kalamazoo, Michigan) and Dr. R. T. Rapala (Eli Lilly and Company, Indianapolis, Indiana), a number of research chemists in their laboratories reviewed those chapters with which they were most intimately familiar. Furthermore, Prof. A.J. Birch (University of Manchester), Prof. Gilbert Stork (Columbia University), Dr. A. L. Nussbaum (Stanford University) and especially Dr. Pierre Crabbe (Syntex, S. A.) examined one or more of these chapters. As a result, the present compendium was reviewed by at least three outside investigators and many of their comments have been incorporated into the final version. For reasons outlined above, the subject matter is covered largely in terms of structural formulae, but, where necessary, brief introductory statements are inserted so as to call attention to the most salient features of a given subject. An exception is chapter 6 (“The’ Birch Reduction”), which represents the only chapter where a single “name reaction” is covered and where no experimental review of the Organic Reactions type has appeared in the literature. It was felt, therefore, that a more extensive discussion, in addition to structural formulae, was indicated.One apparent drawback of these chapters should be noted. For any given transformation (for example, the Introduction of a double bond by oxidation with dichlorodicyanoquinone) all or most of the examples recorded in the steroid literature are given, without any recommendation as to which set of experimental conditions is to be preferred. This was done on purpose, because no single individual has the experimental background to make such recommendations (without direct comparison) for such a variety of reactions, even though the nature of the substrates is often rather similar. I felt that a list of the different conditions employed for any given transformation would be of great utility to the user and that the reported yields could be employed as guidelines to the relative effectiveness of several given sets of conditions, although It should be appreciated that, at times, no attempt had been made in the original literature to develop optimum conditions. If the present book finds a wide audience and the response warrants it, consideration may be given to the preparation of a companion volume – prepared by individuals experienced in given reactions – where a few selected “best” examples of detailed experimental conditions are listed, somewhat similar to the approach used so successfully in Organic Reactions.The principal users of the present book should probably be the following: the graduate student or the research chemist who may have had no personal experience in performing a particular reaction covered in this book and who would like to find quickly the details for appropriate conditions to accomplish a certain reaction which may be completely outside the steroid field; the steroid chemist, who will find some very useful (and often complete) listings of topics important to his work, and who can use this material in conjunction with a complete book such as Fleser and Fieser’s Steroids; and, finally, that rapidly becoming extinct breed of organic chemist, the literature browser, who will encounter stimuli to ponder a multitude of unsolved problems.First and foremost, I must thank the authors of the chapters for having spent the better part of a pleasant California summer in the library, and two of the authors – Miss Dorothy M. Feigl and Mr. Robert H. Shapiro – for having re-typed and re-drawn the entire material In form suitable for direct reproduction. The editor and the authors are deeply grateful to the substantial number of research chemists at Syntex, S. A., The Upjohn Company, and Eli Lilly and Company, who spent many hours in going over this material and who provided numerous helpful comments.