In my earlier book on the Rigveda, I examined the Rigvedic data in detail, and showed that the chronological order of the ten Books of the RV is: 6,3,7,4,2,5,8,9,10, with different parts of Book 1 covering the periods of all but the three earliest Books. I also showed in systematic detail that Family Books 6, 3 and 7 belong to the Early period, Family Books 4 and 2 to the Middle period, and the rest (Book 5 among the Family Books, and all the other, ie. non-family, Books, 8, 9 and 10, and most of Book 1) belong to the Late period.