I do not know of any book or published paper devoted to Cleostratus. In the indexes to most histories of astronomy you will seek his name in vain, and, where you do find it, you are referred to a few jejune paragraphs or more often to a single sentence. Boll in his Sphaera (1903) honours him with three pages (191–194), based on a passage in Pliny and a scholium on Euripides, but he misinterprets both passages and holds one of them to be based on a misunderstanding of some older writer. Nearly all the passages bearing on him are to be found with notes of varying value in Diels, Fragmente der Vorsokratiker, ii. (1912), pp. 197, 198, where they occupy rather more than a page. Some valuable comments and one reference which is not in Diels will be found in Breithaupt's treatise De Parmenisco Grammatico (1915). And yet, for all this neglect, there are attributed to Cleostratus two capital contributions to Greek astronomy, viz. the introduction of the signs of the zodiac and the authorship of the eight years' cycle of intercalations.