I came across this well reviewed book on Amazon, but it seems filled with rather dubious arguments and claims that massage facts to fit the "not about slavery" narrative.
I was wondering if there were any Civil War historians familiar with the book that could point out what might be valid (if anything), and then where the author is stretching or bending the truth or outright lying to create arguments to support his dubious assertion that the war was not about slavery.
As well, I was wondering if their were any historians familiar with this Author and his work in general who could shed light on what (if any) reputation he has in the Civil War Historian community.
Most of the long form reviews, all positive, seem to be highly conservative sites couched in the idea that this book is "anti-PC"...I wasn't really able to find a review that seemed impartial or remotely critical (which seems odd regarding a historical work about the largest conflict in American history), which lead me to ask here.
I've written previously on this, the main response of which can be found here. One day I need to go through and do some small updates to it, as I wrote it six years ago, and there have been so many amazing books written since then which I want to add in, but it remains a pretty solid piece, if I might toot my own horn slightly.
In addition to that, I would point to several more pieces which discuss the Lost Cause narrative that underpins this work of "history". Hot off the presses as I literally spent this morning writing it is this little bit about Robert E. Lee and his place of pride in the Lost Cause. This one in turn looks at the memory of Jackson and attempts to present him as an anti-slavery figure. This one then looks at Confederate statuary and memorials and their relationship to the Lost Cause. I'd also encourage people to check out this post which provides an extensive list of suggested readings on the topic of Civil War memory and the Lost Cause.
I will though add on briefly here for some addendum on the specific thing you're asking about. Samuel W. Mitcham, Jr. is not a reputable historian. His primary focus is writing about the German military in World War II, where he writes a lot of books that people who love rivet-counting explanations of how many MG-42s a German division in the spring of 1943 would be fielding no doubt love, but less good for anyone who actually wants good history about the war. To say that reviews of his work by academics are harsh would be charitable. Lee Baker's review of The German Defeat in the East, 1944–1945 in The Journal of Slavic Military Studies is absolutely cutting, so I'll quote the conclusion in full:
It is no longer possible to write an acceptable history of the Eastern Front which relies solely upon German sources or obsolete interpretations from the Cold War era. The focus is so concentrated on German accomplishments that we learn which Germans won what medals and why, which German units did what and how many Soviet tanks were knocked out, but learn nothing about the accomplishments of the Red Army or how it happened that the German army was defeated, which seems very odd given that this is supposed to be a history of how the Soviets defeated the Germans. The Red Army is reduced to a cipher upon which the Germans work their magic and, despite German courage and skills, some- how manages to win the war (it is not quite clear how this was accomplished). The nearly complete absence of the Red Army is a serious drawback which seriously limits its usefulness to non-specialists (it is of no use to specialists). This is a very old fashioned book whose interpretations of the battles perpetuate obsolete ideas about the Eastern Front; it should therefore be avoided by non-specialists.
In The Journal of Military History James Corum somehow manages to be even worse when he concluced:
Of the many histories of the Wehrmacht that I have read and reviewed over many years this ranks as perhaps the worst. Even the propaganda-laden stuff put out by the Soviet Union in the 1970s was better than this. At least those books could be mined by a historian for useful details, statistics, and maps as long as one was willing to wade through a mass of communist verbiage. But The Rise of the Wehrmacht serves no purpose at all other than to revive many of the myths about the Wehrmacht that should have been put to rest long ago. The $125 the publisher is charging for these books would be better spent buying a volume or two of the German official history.
His switch to writing apologist schlock about the American Civil War seems to be a fairly recent one, so his It Wasn't About Slavery is a bit too new to have any academic reviews - assuming anyone even bothers - but he did write a book about Gen. Forrest a few years prior, and it should be telling that while there is a positive review (I could find no academic reviews of this one), it is from the Abbeville Institute Press, which is in of itself telling, as they are a neo-Confederate apologist outfit run by a member of the Sons of Confederate Veterans, and is the kind of group which gets profiled by the SPLC as a hate group.
So the links hopefully answer the Civil War questions, but as to Mitcham himself, hopefully that is sufficient illustration that you can safely toss the book in the trash if you are unfortunate enough to have ended up with it.
I can't speak to Mitcham's book specifically, but the Civil War was about slavery.
I have answered a few questions before on the Civil War before and the FAQ linked will provide you with plenty of information. But about Samuel Mitcham
You would be correct to be cautious about trusting the books that come out of Regnery Publishings. Their other books include Politically Incorrect Guides to many topics that are part of the larger culture war going on in the United States right now. Books like Politically Incorrect Guide to Climate Change, Politically Incorrect Guide to Communism: The Killingest Idea Ever, and "Why American Muslim groups and left-wing academics are engaged in a huge cover-up of Islamic doctrine and history".^(1) Samuel W. Mitcham Jr. has spoken at Sons of Confederate Veterans meetings. ^(2&3) Mitcham is incorrectly listed as having taught as West Point on that website, so please ignore it. While I have not read his book and do not intend to, I gave a few pages a glance over. Mitcham refers to the Civil War as a war over finances and a war of 'self-determination'. He uses the term self-determination several times. Mitcham frames the Civil War as a war fought by an independent government in order for it to determines its own statehood, alliances, treaties, laws, etc.
One could argue, perhaps, the Civil War was indeed a war of self-determination, right? The Confederacy did want (and did do for four years) to create its own laws, constitution, and treaties. What is dangerous of what Mitchum is doing is using Neo-Confederate and Lost Cause terminology when he refuses to expand on why this war of 'self-determination' was fought. Confederate Vice-President Alexander Stephens laid it out for us, quite clearly. Stephens acknowledges that in the past and up to that point (1861) that there were disagreements about the morality and legality of slavery in the United States.
"The prevailing ideas entertained by him [Thomas Jefferson] and most of the leading statesmen at the time of the formation of the old Constitution were, that the enslavement of the African was in violation of the laws of nature; that it was wrong in principle, socially, morally and politically."
Stephens goes on to state explicitly that enslavement of Africans and African Americans is the reason for secession and for war.
Our new government is founded upon exactly the opposite ideas; its foundations are laid, its cornerstone rests, upon the great truth that the negro is not equal to the white man; that slavery, subordination to the superior race, is his natural and normal condition. This, our new government, is the first, in the history of the world, based upon this great physical, philosophical, and moral truth. This truth has been slow in the process of its development, like all other truths in the various departments of science.
This is where Mitchum, in my limited exposure to his book, deviates intentionally from the truth. He attempts to frame the war as a purely economic war in which the Confederacy is seeking to fight against the Union for the 'noble' cause of independence and freedom from an overreaching federal government, a popular bit taken from Lost Cause believers. He is not a respected historian, to say the least, and his use of a Ph.D. does nothing but allow him to add a poorly disguised layer of 'credibility' (in the eyes of his readers) to the lies that Lost Causers and Neo-Confederates continue to spout.
When are books scholarly?
1)https://www.regnery.com/series/
2) http://www.stephendleeinstitute.com/events.html
3) https://www.newsobserver.com/news/local/article240670326.html
Just to add some further reading to the great stuff already in here, users might enjoy the following threads as well. Especially as this kind of question often leads to questions about the motivations of Southern soldiers.
/u/Georgy_K_Zhukov on Was the average Confederate soldier a strong proponent of white supremacy?
and /u/freedmenspatrol on Aside from States' Rights to own slaves, what "States' Rights" were Confederate soldiers fighting for?