A NATO Advanced Study Institute on "Molecular Mechanisms of Transcellular Signaling: from the Membrane to the Gene" was held on the Island of Spetsai, Greece, from August 15- 27, 1994. The aim of this Institute was to bring together researchers in the field of signal transduction mechanisms, transcription factors and gene regulation with those actively involved in studies on the implications of oxygen radicals and antioxidant defence mechanisms for cell function. As diverse as these fields may be, the emergence of their interconnection during the course of the Institute was an eye-opener for students and lecturers alike. 2 Presentations and discussions focussed on the role of Ca +, G-proteins, protein kinase C and phospholipases in signaling mechanisms. These broad principles were extended to transcription factors and gene regulation with an emphasis on the steroid hormone receptor superfamily and NFKB. Basic principles of free radical formation and antioxidant action (vitamin E and C) were presented and discussed in connection with effects on signaling pathways. This book present the content of the major lectures and a selection of the most relevant posters. These proceedings offer a comprehensive account of the most important topics discussed at the Institute. The book is intended to make the proceedings accessible to a large audience.