Weak interactions and higher symmetries are nowadays of special importance for elementary particles theory. Lately both theoretical and experimental physicists became more and more interested in the subject. Because of the complicated subject and the scarce available literature proper introductions in the subject are tiresome. The mathematical back­ ground such as higher Algebra and Grouptheory etc. cannot be applied immediately in all cases. The third Schladming University Courses on the above subject belong to this category. The present first supplement volume of "Acta Physica Austriaca" contains all lectures (with literature references) giving not only a review of the fundamentals but also discussing recent research work. I ,;incerely hope that the pUblication will find interested readers. In the last years it became customary in physics and mathematics to arrange summer schools on subjects which allow the experienced as well as the young scientiflt to get quickly acquainted with special modern fields. Discussions and private contacts make it possible for participants to touch quickly the peripheries of the subject in question, and new research work will be stimulated which otherwise could not be expected. Graz, October, 1964.