Reddit reviews A History of China

Anything by Petter Hessler (Country Driving, The Oracle Bones) or James Fallows (China Airborne, Postcards from Tomorrow Square).
Both were long-time journalists posted in the country, Fallows for The Atlantic, and Hessler for New Yorker/Nat Geo, I think, and both do an excellent job of simultaneously capturing the political, commerical, and human sides of the transitions currently wracking China.

Additionally, I'm a big proponent of learning a country's history in order to understand its culture. Wolfram Eberhard's History of China, is excellent, comprehensive, and free on Kindle. I recommend it.

http://www.amazon.com/History-China-Wolfram-Eberhard-ebook/dp/B0084991IG/ref=sr_1_1_twi_1?s=books&ie=UTF8&qid=1419117875&sr=1-1&keywords=chinese+history

If you're talking specifically post-Qin, there are huge variations in levels of continuity (or noncontinuity) between subsequent dynasties. I'm not knowledgeable enough first-hand to comment in detail on the subject, but I'm reading Wolfram Eberhard's A History of China, which is available for free on Kindle. Certainly around the Three Kingdoms (right after Han) and then around the Northern and Southern Kingdoms (right after Jin, before Sui) the country had fragmented into largely separate landed polities vying for control. The Three Kingdoms fragmentation lasted six decades; the North-South Kingdoms lasted over a century and a half. These are significant enough that I would consider "Qina" as a state to have broken up during those times, and thus the concept of unbroken imperial rule from Qinshihuang to be untenable.

In addition, there was the constant external pressure by various non-landed ethnic groups, which themselves did not exist in a state of unchanging stasis, but also intermarried, supported, betrayed, opposed, and otherwise interacted with the people of the post-Qin kingdoms. Eberhard's recounts a dizzying array of peripheral clans, muting from one to the next, sometimes seizing power and marrying into the settled families and kingdoms. Xiongnu, Huns, Turkics, Sogdians, Uyghurs, and Tibetans are all mentioned as key concerns with profound effects on the stability of the central cosmopolitan regions.

While Qinshihuang was the first ruler to declare himself an emperor with the title of Huangdi, Eberhard maintains (and I agree) that it's oversimplistic to claim that he "founded China as we know it". Later non-Imperial kingdoms exceeded his territory, influence, and population individually without ever unifying the nation.

Instead, Eberhard terms "modern China" as starting from the late Sui and early Tang, whereupon a historian could more confidently claim an unbroken (or near-unbroken) line of Imperial command across dynasties. Prior to that, when empires collapsed into long-term squabbling intermediary kingdoms, Eberhard terms the period of "medieval China".