Solar deities are some of the most significant and diverse figures of the pantheon revealed in the cuneiform tablets of the Hittites. Drawn from a wide range of Anatolian and Syro-Mesopotamian traditions, the Hittite solar deities include Sun-gods and -goddesses who display an array of differing attributes and represent both the celestial and chthonic spheres. Yet the relevant sources (for the most part written in Hittite, but also in other languages) do not necessarily distinguish these solar deities from one another by proper names or distinct logograms. Previous elucidations of the solar deities rested in many respects upon doubtful methodologies or tenuous axioms. This study provides a new approach to distinguishing the solar deities by combining diachronic and typological criteria with careful attention to the cultural milieu of the individual source texts. From this methodology emerges a functional description of the sub-types of solar deities as they relate to various Hittite cult practices, mythological traditions, the systematic conceptualization of the pantheon as well as the Hittite ideology of kingship. Separate treatments of Old and Middle Hittite texts highlight both innovation and continuity of the role of the solar deities in the history of Hittite religion. A model is proposed as to how the solar deities came to co-exist in the religion of one of the major Bronze Age civilizations of the Near East. Furthermore, by considering all text genres from the early Hittite kingdom, this monograph serves as a useful synthetic compendium of sources both of the Hittite solar deities and of the formative period of Hittite religion in general.