When summer came is unknown at present, and neither is the earliest version. Judging from the current data, Summer was originally just an article in The Story of Dai Dai, but later people found it more useful, so they compiled it into a separate book. And because of its high practicality, there are many supplementary versions in the process of circulation. It was difficult to collect and sort out these editions in ancient times, so Xia Zhengxiao is still a rather messy book? An encyclopedia? Yes
Of course, some people think that Xia Zhengxiao is a book of cultural rumors about the Xia Dynasty collected by Confucius' disciples when they traveled around the world. What is certain, however, is that Xia clearly recorded the related matters of China's lunar calendar, such as weather, seasons and meteorology. Which is very scientific? Scientific literature? Category.
Generally speaking, it is uncertain whether Xia Zhengxiao came from Xia Dynasty. After all, the existence of the Xia Dynasty is still a mystery, but the agricultural calendar information recorded in the book is still of great significance to today's scientific research, so it is not an exaggeration to call it the earliest scientific literature.