The Brooksher book is reasonably well written and readable. It gives a good overview for a general reader. I do not consider it to be a substantive contribution, particularly relative to the historical literature and archives of the western Louisiana region, or the needs of a historian.
As a footnote, I noted the coming availability of the 1st volume of the Petersburg Campaign series and have done a pre-publication order. I am looking forward to seeing them.
Very best
Don Parker