In Egypt, from the Old to the New Kingdom, enigmatic texts were created on the basis of non-standardized lists of characters and phonetic signs, the exact principles of which are still unclear to this day. For the first time, this study examines in detail the three most comprehensive known inscription texts from the New Kingdom, which were discovered in the tombs of Tutenchamun, Ramses VI and Ramses IX. Darnell shows that these three texts have a theological, iconographic and formal connection, and calls them collectively the "Book of the Solar-Osirian Unity". Differentiated and lively, he presents the content and theological peculiarities of these texts that deal with the afterlife with each other and in relation to other enigmatic texts of the new as well as the Middle and Old Kingdom.