I read this book in my friend's house and I would only consider this book an 'opinion book', not a well-referred, well-researched academic study. I can't do it when the author wouldn't even tell me where his information and references came from.
However, the author's opinions on the development of history and political viewpoints are indeed refreshing!
(1) We cannot stress this enough, but mainstream history always downplays the influence of the Arabic world and the Central Asian countries on China.
(2) We also cannot stress this point enough! The so-called Chinese nationality and national identity is a myth built around the time of the late era of the Qing Dynasty, it is a myth built out of convenience and political needs, and it is barely an organic, fully-formed, and well-defined identity!
(3) We also cannot stress this enough! The greatest and the most powerful 'Han' dynasties in Chinese history, e.g. the famed Tang Dynasty and the Qing Dynasty, its royal families are either not fully Han, or just entirely non-Han when ethnicity is concerned.
(4) However, the author's view that different civilizations have different levels of achievement and importance can be...controversial in the current time. Especially when the author thinks the Western civilization and the Arabic and/or the Central Asian civilizations have been more advanced in history and these 'outsider' civilizations were in fact the driving forces beyond the development of Chinese society and technology, etc.
(5) It is another interesting read to let us reconsider what we have been taught about 'Chinese history', the relationship between civilizations, the 'Outsiders' and the 'Established', or even who are the outsiders and who are the established, etc.