On that day, nearly 20,000 (19,240) British soldiers died and nearly 36,000 (35,493) were wounded.
This is the most complete account of that bloodbath you are ever likely to read.
The magnitude of the catastrophe still beggars the imagination.
Only the use of a nuclear device could have had the same impact, and those were still decades in the future.
And unlike a nuclear device, the weapons available in 1916 still killed individually.
This was a very personal holocaust.
The tradition among the British people has been that this was a failure of British generalship, of almost universal incompetence.
The implication is that the British generals did not know their business and did not care.
That is an easy conclusion to draw but is, of course, an oversimplification.
British generals had had nearly two years to learn their trade; many had not.
They wilfully ignored the greatest military asset, surprise.
Tactical innovations were beginning to appear among the main contenders in what was becoming known as "the Great War'', but were not yet widespread and some British commanders still had a very poor opinion of the troops they commanded.
"Lions led by donkeys'' was the opinion of their German opposites.
The one quality in which the British troops were not deficient was courage.
This they had in abundance, to their own undoing.
It is impossible to read this book without experiencing the twin emotions of sorrow and anger.
The Somme campaign was to continue for five months until winter set in.
After capturing a few yards on the first day, British attacks gradually became more successful.
By November, a few miles of northern France had been captured.
Each gain gave the British hope and so they persisted.
The word "attrition'' began to appear in self-justificatory reports.
And so it ground on and on.
Many, many thousands of Germans died too which, hopefully, was of some comfort to the grieving families of those mourning.
It is estimated that by the time winter had set in, casualties (killed, wounded, missing and prisoners) totalled about 1.28million officers and men of all the armies involved on the Somme - including 420,000 British, 205,000 French and 660,000 Germans.
This book is limited to the opening day.
The reader cannot help wondering what was the point of it all.
Perhaps a history should not stray into moral questions - whether it was all worth it - although any eventual outcome may have lessons on that.
There were no New Zealand units present on the first day of the Somme.
Otherwise July 1, 1916 would surely match Anzac Day as a red letter day in our history.
- Oliver Riddell is a retired journalist in Wellington.
