Here is a passage from chapter VI "The Chaldeans" from the English version of the book: "The British Betrayal of the Assyrians" by the giant Assyrian Yousif Malek (A member of the Chaldean Catholic Church). Please observe how he states the truth as simple as it can be stated when he refers to the members of the Chaldean Catholic Church as the "SO-CALLED Chaldeans" and how he later mentions that we are all Assyrians but divided into (5) RELIGIOUS SECTS.
During the recent years, there have been many cases of inter-marriages between the two family branches, for, with the exception of minor religious beliefs, there is no difference whatsoever between them. Their traditions, customs, and usages are one. Theologically, the difference is of no importance, but the only apparent difference is that the Assyrians, highlanders as they are, were able to maintain their fighting characteristics, in the inaccessible fastness of Kurdistan, which the Chaldeans were unable to do in the plains.
The term, "Chaldean", was originally given to the members of the Church of the East, who lived in Iraq, first, for their geographical situation, and second, for the historical surroundings. There still exists, in possession of Mar Eshai Shimun, Patriarch of the Assyrians, a historical seal dating centuries back, used by his predecessors in sealing all the documents that emanated from the Patriarchal See. The seal which I have seen has the following inscription:
"Humble Shimun, Patriarch of the East, by Grace serving the See of Thaddeus (Addai)."] (page 65-66)
Then, from Chapter VII, Yousif Malek writes;
"The Assyrians, although representing but ONE SINGLE NATION AS THE DIRECT HEIRS OF THE ANCIENT ASSYRIAN EMPIRE as indicated in chapter 1, are now doctrinally divided, inter sese, into FIVE PRINCIPLE ECCLESIASTICALLY DESIGNATED RELIGIOUS SECTS with their corresponding hierarchies and distinct church governments, namely, Nestorian, Jacobite, Chaldean, Maronite and Syrian Catholic. These formal divisions had their origin in the 5th century of the Christian era. No one can coherently understand the Assyrians as a whole until he can distinguish that which is religion or church from that which is nation--a matter which is particularly difficult for the Oriental people to understand; for in the East, by force of circumstances beyond their control, religion has been made, from time immemorial, virtually into a criterion of nationality." (page 103)