Over the past year or so I've taken an interest in Chinese history, particularly the ancient and classical eras where some of the most famous events took place, like in the Three Kingdoms era. However one thing that has always struck me is that historians' understanding of these eras seems to have traditionally relied on only a few secondary sources, namely the histories of these periods written after the fact, along with any surviving annotations or commentaries on those works.
How has our understanding of these times evolved in recent times? Have historians been able to cast a more critical eye at these traditional sources, or have other forms of evidence come available which have shaped the way we view these periods? Have there been any studies which look at areas often overlooked in traditional histories, like the lives of the lower classes or women in these societies?
This is not to say that the question has been totally answered already (and you may have already seen this), but u/cthulushrugged's answer to a question about the historicity of the Xia in last month's panel-AMA on East Asia will interest you. If you have online access through an institution, or perhaps the print copy is in a local library, their key source was Kwang-Chih Chang's chapter in the Cambridge History of Ancient China. Chang's chapter dates to 1999, and (it seems) mostly deals with a paradigm shift starting in the 20s.
In fact, the whole thread is gold. With regards specifically to early Chinese history:
Your last comment about women, the lower classes, and other groups on the margins of official histories is a very good point, that I would also love to learn more about!