Sun Lore of All Ages by William Tyler Olcott [1914]

This is a review of the literature of Sun lore. While for the most part factually correct, this is not an academic study. Olcott is light on the citations, and it apparent that he didn't use primary sources for the vast majority of the myths. But by far the biggest problem here is the reliance on the 19th century 'solar mythology' theorists, in which every myth and scrap of folklore was interpreted as some symbolic aspect of the sun, the solar year, the water cycle (!), and any other concievable sun-related phenomenon. That said, this is one of those books that makes fascinating reading, whether you read it end-to-end or are just browsing.