Author tries and fails to wins operational goal by using attritionist tactics
This is not a history book describing the Battle of the Somme as it happened. This book has an "operational" agenda, to try and refute the "myth" that the Somme was a big useless waste of human material for extremely little gain.
To do this, the author tries to employ the same attritionist tactics that he so advocates in his book. -He scrapes up every reasonably credible quote of heavy German casualties and failing morale (to his credit, he DOES mention that French and British morale is cracking though supposedly not as much as the Germans). -He tries to say the goal was attrition all along, and that it was a "break-in" rather than a "break-through" (though he is forced to admit at least at some point Haig was hoping for a break-through), and even tries the deny the value of taking territory. -He keeps repeating, like a mantra that under the circumstances attrition (and inefficient attrition at that) is the best that could be expected. -And he catalogues every tiny success the Allied forces had. The entire mid-section of the book is filled with countless "Division X attacks and grabs Y village".
Yet, the excessive detail actually is his worst enemy. The need to keep writing this kind of insignificant stuff over and over, along with very large-scale maps making clear how slow the going really was, convince the reader that the conventional variant is close to the truth. Add some healthy skepticism of his choice of statistics and quotes, and his "attack" bogs down just like the Somme, leaving the reader almost as fatigued as the soldier on the front for no operational gain...