The textbook Geometry, published in French by CEDICjFernand Nathan and in English by Springer-Verlag (scheduled for 1985) was very favorably re ceived. Nevertheless, many readers found the text too concise and the exercises at the end of each chapter too difficult, and regretted the absence of any hints for the solution of the exercises. This book is intended to respond, at least in part, to these needs. The length of the textbook (which will be referred to as B] throughout this book) and the volume of the material covered in it preclude any thought of publishing an expanded version, but we considered that it might prove both profitable and amusing to some of our readers to have detailed solutions to some of the exercises in the textbook. At the same time, we planned this book to be independent, at least to a certain extent, from the textbook; thus, we have provided summaries of each of its twenty chapters, condensing in a few pages and under the same titles the most important notions and results, used in the solution of the problems. The statement of the selected problems follows each summary, and they are numbered in order, with a reference to the corresponding place in B]. These references are not meant as indications for the solutions of the problems. In the body of each summary there are frequent references to B], and these can be helpful in elaborating a point which is discussed too cursorily in this book."

The textbook Geometry, published in French by CEDICjFernand Nathan and in English by Springer-Verlag (scheduled for 1985) was very favorably re ceived. Nevertheless, many readers found the text too concise and the exercises at the end of each chapter too difficult, and regretted the absence of any hints for the solution of the exercises. This book is intended to respond, at least in part, to these needs. The length of the textbook (which will be referred to as B] throughout this book) and the volume of the material covered in it preclude any thought of publishing an expanded version, but we considered that it might prove both profitable and amusing to some of our readers to have detailed solutions to some of the exercises in the textbook. At the same time, we planned this book to be independent, at least to a certain extent, from the textbook; thus, we have provided summaries of each of its twenty chapters, condensing in a few pages and under the same titles the most important notions and results, used in the solution of the problems. The statement of the selected problems follows each summary, and they are numbered in order, with a reference to the corresponding place in B]. These references are not meant as indications for the solutions of the problems. In the body of each summary there are frequent references to B], and these can be helpful in elaborating a point which is discussed too cursorily in this book."

tens sowie der Bruchspannung und Festigkeit, immer wieder ergiinzt durch molekulare und andere Modellvorstellungen. Es folgt dann ein Ka- pitel mit kritischen Betrachtungen uber die technologischen Priifmetho- den. In den folgenden drei Kapiteln werden die Zusammenhiinge zwischen der Struktur und den mechanischen Eigenschaften von kautschukartigen und plastischen Korpern sowie von Faserstoffen behandelt. Dabei sind nur solche Untersuchungen berucksichtigt, die fUr die Entwicklung un- serer Kenntnisse der Eigenschaften hochpolymerer Korper und fUr das Verstiindnis ihrer Beziehungen zur molekularen Struktur von allgemeiner Bedeutung sind. Derartige Untersuchungen sind aber nur an relativ wenigen Stoffen durchgefUhrt worden. Den Zusammenhiingen zwischen Struktur und elektrischen Eigen- schaften ist, ebenso wie der Weichmacherwirkung und ihrer molekularen Deutung, ein besonderes Kapitel gewidmet. SchlieBlich wurden im letzten Kapitel einige allgemeine Zusammenhiinge zwischen der molekularen Struktur und den makroskopischen Eigenschaften von hochpolymeren Korpern herausgestellt. Hierbei kann es sich nur urn einen ersten Ver- such handeln, der zu weiteren Arbeiten anregen moge. Es ist mir eine Freude, allen Mitarbeitern fUr ihre Mitwirkung und fUr ihr Eingehen auf die Wunsche des Herausgebers vielmals zu danken, insbesondere den Herren STAVERMAN und SCHWARZL, die wesentlich dazu beigetragen haben, daB dieser Band in der gewunschten Form und rechtzeitig erscheinen konnte. Herr O. FUCHS, Hochst, hat auch bei diesem Bande die gesamte Kor- rektur mitgelesen und manchen Verbesserungsvorschlag gemacht, wofUr ihm auch im Namen der Mitarbeiter herzlich gedankt sei.