This volume contains most of the lectures presented at the meeting held in Carry-le nd Rouet from the 2 to the 4th June 1980 and entitled "Numerical Methods in the Study of Critical Phenomena." Scientific subjects are becoming increasingly differentiated, and the number of journals and meetings devoted to them is continually increasing. Thus it has become very difficult for the non-specialist to approach subjects with which he is not familiar. Hence the purpose of our meeting was to bring together scientists from different disciplines to study a common subject and to stimulate discussion' between participants. We hope this goal was reached. The lectures are grouped in five chapters and, inside the first and the second chapter, under two headings. In each group they are classified in alphabetical order by author. We are pleased to publish these Proceedings in a series whose multidisciplinary character has been emphasized from the beginning. We are indebted to all who provided us with their help, particularly to Mrs. A. Litman of the Centre International de Rencontres Mathematiques at Luminy (C.I.R.M.) whose kindness and efficiency are well known; from the practical point of view, the meetings were organized within the scientific framework of the G.I.S. No.19 (C.N.R.S.), with the participation of the University of Grenoble."

This volume contains most of the talks presented at the Journ~es de la Soci~t~ Math~ma~ique de France entitled "Rhythms in Biology and other fields of application -Determi- nistic and Stochastic Approaches" held in Luminy from the 14th th to the 18 of September 1981. The aim of our meeting was to bring together scien- tists from different disciplines to discuss a common topic and to stimulate exchanges between participants. We hope that this goal was reached. This volume is divided into four chapters. In each one the papers are arranged in alphabetical order by first author. Chapters one and two contain papers devoted to descrip- tion or modelling of rhythmic biolog.ical phenomena. Chapters three and four deal with models for the study of rhythms invol- ving the use of deterministic or stochastic tools capable of fruitful transfer to Biology. We are pleased that these Proceedings appear in a series which constitutes an interface between Biologists and Mathema- ticians. We are indebted to all who provided us with their help, particularly the Centre International de Rencontres Math~matiques (C.I.R.M.) at Luminy, the Soci~t~ Mathematique de France (S.M.F.) , the Delegation aux Relations Universitaires Internationales (D.R.U.I.) and the Laboratoire d'Informatique et de Math~matiques Appliquees de Grenoble (I.M.A.G.). Special thanks are due to Mrs. A. Litman for her dedi- cation and her efficiency throughout the organization of this meeting. G~enobie, Vecembe~ 1982.