The present study of sense and reference in the logic of Frege represents the first fruits of several years of dealing with the work of this great German logician. In the preparation of this work, which was presented as a dissertation to the Faculty of Philosophy of the Friedrich-Alexander University in Erlangen/Nuremberg, assistance came from many quarters. lowe most to Professor R. Zocher, who directed this dissertation with understanding counsel and unflagging interest. I must also thank Professor P. Lorenzen, whose courses and seminars provided more inspiration than might be immediately apparent in the book. Professor W. Britzelmayr of Munich was so kind as to provide copies of important fragments of Frege's works. These texts are reproduced with the permission of Professor H. Hermes, Director of the 'Institut fUr mathematische Logik und Grund- lagenforschung' in Munster, where Frege's works and letters are being prepared for publication. The preparation of this work was greatly facilitated by a two-year grant from the Fritz Thyssen Foundation. CHRISTIAN THIEL Nuremberg, February 1965 v TRANSLATOR'S NOTE In the difficult matter of Fregean terminology we have taken Ignacio Angelelli's translation of Two Soviet Studies on Frege as the model. Both Professor Angelelli and Dr. Thiel have been so kind as to read over the translation before publication.