The papers assembled in this volume are based on the symposium on The Biochemistry of Gene Expression in Higher Organisms which was held at the University of Sydney from May 14-19, 1972. Many symposia have been held on the control of gene expression in prokaryotes but to date considerably less attention has been paid to eukaryotic organisms. It has been appreciated only recently that some of the information gained from the study of prokaryotes is directly applicable to eukaryotes; however, it is now realized that the principles of the control mechanisms of gene expression in these two classes of organism, differ considerably. This symposium was organized in an effort to bring together workers from widely different fields concerned with gene expression, with the aim of circum scribing the current concepts and speculating on future developments in studies on the mechanisms which control and modulate gene expression, in the widest sense, in eukaryotes. This volume contains all the 36 papers presented at the symposium. In a few instances the sequence of contributions has been changed to provide the reader with a more logical presentation. In addition, three papers which were not actually presented at the symposium, have been included in this volume. These three papers were not read because last-minute hitches prevented speakers from attending.