The chapter discusses the deduction of the widespread nineteenth century concept of ethical monotheism from Maimonidean sources – as it was indeed attempted by several Jewish scholars before Hermann Cohen and as it eventually culminates in Cohen's works on Maimonides. Cohen relies, as far as he draws on Jewish sources for his definition of this concept, essentially on a radical re-interpretation of Maimonides' famous doctrine of the divine attributes from the Guide of the Perplexed. Concerning the Wissenschaft movement, it will be shown how out of the renewed interest in Maimonides' philosophy in Germany in the second half of the nineteenth century, there emerged a certain development of thought about Maimonides' concept of God. This development in the interpretation of Maimonides, guided by the thinker's interest in modernizing and purifying the Jewish idea of God, led eventually to the outstanding results in Cohen, but even beyond Cohen – for Cohen's central thesis, that the real aim of Maimonides' religious philosophy is purely ethical, did not remain unchallenged in his own school, as the chapter shows. Cohen demonstrates in a sophisticated argument that Maimonides' "negation of privation" technique turns the apparently negative attributes of God in fact into attributes that are "more positive, because they are more prolific than the positive attributes." By associating the Maimonidean technique of "negation of privation" with the logical category of infinite judgment, Cohen is able to construct a concept of God that is not only similar to the Platonic idea of the good beyond being, but also one that is highly compatible with the Jewish traditional God of Bereshit, the Creator of the universe.