Regarding official regimental histories:
These have evolved enormously. In the 1950s there was a huge rush to get regimental histories published. By and large, these volumes suffer from several drawbacks, mostly related to the fact that they were usually written by officers who had served in the regiment in combat.
Why is this a drawback? Firstly, the books contain a considerable amount of jargon, but moreover, are written as if the reader knows perfectly well how a company would conduct a deliberate assault, say. They were written by a serving soldier as if only other serving soldiers would ever be interested in them.
Secondly, they were written at a time when other serving officers were still alive. There is practically no criticism of any kind in the history, no judgements, simple recitation of the facts.
Thirdly, no attempts are made to look at German records or record "the other side". They are all one-sided stories, usually replete with names and dates that have little meaning, since the books of the time often did not have a single photograph in them, or if they did, they were stock photos usually not even depicting the regiment in question.
In the last 10 or so years, we have seen a renaissance in regimental histories. Use of photographs to illustrate these volumes has improved due to the lower costs or reproducing same, as well as veterans probably being more lenient with loaning out photos than they were in the 1950s, when they probably just wanted to forget what they went through "over there."
Authors today tend not to belong to the regiments they are writing about, and are free to discuss all aspects of the regimental history with greater freedom. Roy Farran, for example, wrote a history of the Calgary Highlanders in the 1950s that dealt in more detail about the mess parties in the 1930s than in the relationship between the COs and the troops. Farran was a highly decorated British officer in WW II and a respected member of Calgary high society, along with other veterans of the Highlanders whom he was then writing about. Compare to David Bercuson‘s history of the Calgary Highlanders, published much more recently. Bercuson is a labour historian and professional scholar, not a soldier, and he was free to discuss the very poor reputation that one of the COs had, and attempt to judge him (or rather, report on how the troops judged him, based on his interviews). Farran gives no clue whatsoever that one of the COs was not well liked.
The earlier regimental histories are to be taken with a grain of salt then; for someone with limited knowledge of Second World War terminology or practices, they will be a tough read. By contrast, Donald Graves‘ history of the SAR has a full fledged battle manual in the Appendices, to explain in basic terms how the regiment operated in battle - a real boon to the casual reader.
Unfortunately, regimental histories still suffer from the very real drawback of not having been researched from the German side of things. This is true of most WW II histories, regardless of nationality. Denis Whitaker is the only Canadian historian I can think of off the top of my head who went out of his way to consult German sources in his writings.