The golden age of Egyptian solar hymns - the three centuries from c. 1500 to 1200 BC which have provided many hundreds of examples of them - is a unique phenomenon. No other period of Egyptian history, indeed no other culture, has produced such an abundance of poetry in praise of the sun god. There are among them an astonishing abundance of hymns that have an individual character and represent the textual expression of the spiritual-religious movement. The spiritual movement that is embedded in and expressed by them is the struggle to articulate a concept of the unity of the divine - the One God. The uniqueness or oneness of god is the central theological problem of the New Kingdom. The Amarna period is striking proof of the historical explosiveness of this problem. It is less well known that the problem was by no means solved with the failure of Amarna religion. There was a continuing attempt to articulate concepts of the unity of god and to harness this conception with the ultimately indispensable reality of polytheism in Egyptian religion during these centuries. The crisis of polytheism is primarily concerned with the conception of god, with questions of unity and plurality that are pushed - long before the rise of monotheistic religions in the proper sense - to the extremes of radical and revolutionary monotheism. The problem confronts us in the texts themselves; it is explicit, central and cannot be ignored. It is the dominant theme of the theological discourse which establishes the contours of Egyptian cosmology at the same time as determining the nature of the divine. The confusion in which Egyptian theology usually appears in the texts produces a degree of complexity that precludes comprehensive understanding of it. In this volume - a revised and expanded version of the original German text - solar religion and the sun hymns of the New Kingdom are studied in the greatest possible detail, with five different traditions distinguished and analysed.