EDITORIAL
	"Unnatural" Products and "Unnatural" Processes.
	by Vincenzo Balzani	1
IUPAC COMMISSION ON PHOTOCHEMISTRY
	Meeting Report.
	by Silvia E. Braslavsky	5
CONFERENCE REPORTS
	Annual Meeting on Actual Theoretical and Applied Problems of Photochemistry ofMetallocomplexes, Zelenogorsk, Russia, March 2-6, 1991.
	by G.A. Shagisultanova	7
	Course in Photoconversion of Solar Energy, Brigels, Switzerland, September 15-25, 1991.
	by Larss Forss	10
	2nd Conference on Methods and Applications of Fluorescence Spectroscopy, Graz, Austria, 14-17 October 1991.
	by Wolfgang Rettig	12
	Third Latin American Meeting on Photochemistry and Photobiology, Mar de la Plata,Argentina, October 21-24, 1991.
	by Silvia E. Braslavsky	15
	Mediterranean Meeting on Photochemistry, Acireale-Catania, Italy, October 28-31, 1991.
	by Roberto Ballardini and M. Teresa Gandolfi	17
	Photochemical Processes on Solid Surfaces, Ferrara, Italy, November 5-6, 1991.
	by Vittorio Carassiti	21
	II NATO Science Forum on Supramolecular Chemistry, Taormina, Italy, December 15-18, 1991.
	by Sebastiano Campagna and Massimo Guardigli	23
	Fourth Winter Conference of the Inter-American Photochemical Society, Clearwater Beach,Florida, January 1-5, 1992.
	by Eva Migirdicyan	27
TOPICAL ARTICLE
	Ground-State Rotamers of 1,2-Diarylethylenes Detected by Techniques Involving Electronic. Excitation: Limits to the Validity of the NEER Principle.
	by Ugo Mazzucato and Fabio Momicchioli	31
TECHNICAL NOTE
	A Thermostatic Absorption Cell for High Accuracy Measurements of Absolute Intensities.
	by D. Hurtmans, R. Pétrisse, D. Lemaître, C. Clerbaux and J. Vander Auwera	40
EPA NEWS
	Grammatikakis-Neumann Prize 1992.	43
	Postscript: Reading, September 1991.	43
	Organizing "Asian Photochemistry Association."	44
	The Porter Medal Award for 1992 to Kenichi Honda.	45
PUBLICATIONS
	Abstracts of Theses in Photochemistry.	46
BOOK REVIEWS
	Photochemical Essentials. Essentials of Molecular Photochemistry.
	by John Coyle	51
	Advances in Gas-Phase Photochemistry and Kinetics Dynamics of Gas-SurfaceInteractions
	by A. Crucq	52
	Tunneling the Mental Barriers to Electronic Theory Electronic Aspects of OrganicPhotochemistry.
	by H. J. Kuhn	54
CONTACTS
	Computer-Assisted Communication with the C.I.S.
	by Werner E. Klotzbücher	56
UPCOMING MEETINGS
	Calendar.	60
	Announcements.	64
NEW MEMBERS		68