The present collection of articles, mainly consisting of new publications, is a critical aprreciation of the work of the logician, mathematicain and philosopher Gottlob Frege. – The first papers of volume II critically deal with Frege's theory of functions and his concept of logic. An account showing the development of his doctrine of judgement is followed by two papers on the theory of quantification. The first discusses Frege's change from a substitutional to an objectual definition of quantification, while the second compares Frege's approach with corresponding reflections of Russell and Quine. Finally, several articles discuss problems of identity in Frege under comparative and analytical aspects.