FOREWORD This book came about as a result of two events: an exhibition on the Solvay Physics Councils, held in Brussels in May 1995, and a conference on the same theme which took place at the Free University of Brussels (ULB) on May 1Oth 1995. A book was published in French in conjunction with the exhibition, and much of the present publication is taken from that book. In addition, we have included some of the papers presented at the conference, as we believe they add a further dimension to the history of the Councils. The French term, Conseil Solvay, is usually translated into English as...