This guide is composed of 18 papers prepared by school and university teachers for school teachers and other curriculum developers. The guide is not intended to be a textbook for the teaching of chemistry in schools; nor is it a detailed manual on how to teach specific subjects. It is, rather, a presentation of those areas of chemistry which, in the course of recent years, have received either an interpretation quite different from the one usually imparted in schools, or an experimental approach such as to render obsolete the treatment normally given. The main object is, therefore, to supply information on theories and well-established facts to present modern approaches to the interpretation of reactions and experiments, and to emphasize novel ways of presenting chemistry in a fashion consistent with the present state of the science and its current development. The authors of the papers have made a special effort to present each topic in terms of fundamental principles so that each teacher can avoid "didactic lies," and so that pupils who go on to more advanced study need not "unlearn" what they have been taught at an elementary stage. (Author/TS)