IT is sometimes said that biographers often come to idolise the men or women about whom they write.
There was never any chance of that when author Nicholas Milton chose as his subject one of the German Nazi regime's s foremost ornithologists, Günther Niethammer.
For much of the 1939-45 war, Niethammer was employed as a guard in the notorious work camp/prison/extermination centre at Auschwitz in Poland.
Although he may not have been involved with the atrocities being committed, he will certainly have witnessed - and stayed silent - about what was going on.
And even as the toll of horror escalated all around him, he used his free time to pursue his longstanding interest in birds - putting up nest boxes for Starlings and Black Redstarts and surveying the birdlife both within the confines of the electric fencing and in the extensive wetlands beyond.
Among the species he observed were Great Reed Warblers, Aquatic Warblers, Black-necked Grebes, Bitterns, Marsh Warblers, Nightingales, River Warblers, Penduline Tits, woodpeckers of various species, Goshawks and Golden Orioles.
It seems extraordinary that Niethammer should have been so callous as to pursue this entirely pleasurable pursuit within the context of human suffering which was increasing by the day.
The only explanation that Milton can find is: "Niethammer was not just surveying birds, he was using them to turn a blind eye to the horrors going on in the camp."
Notwithstanding, there is value in Niethammer's ornithological research - much of it recorded in his paper, Observations on The Birdlife of Auschwitz, Eastern Upper Silesia, an important source for his biographer.
Despite the profusion of birds of many species, some - such as Blackbird, Song Thrush and Grey Wagtail - were surprisingly scarce.
How was Niethammer allowed to indulge himself in his favourite pursuit for so much of his time?
Reading between his biographer's lines, it seems he inveigled himself into the favour of Auschwitz's ruthless Commandant, Rudolf Hoess - the perpetrator-in-chief of the atrocities and responsible for more than a million deaths.
Captured after the war, Hoess was hanged for his war crimes while Niethammer was imprisoned - but only for a relatively short time.
After his release, he was, in 1949, able to resume what proved to be fulfilling career in ornithological research at the Zoological Museum Koenig in Bonn where he was appointed curator of birds.
Although he doubtless regretted his involvement with what happened at Auschwitz, there is scant evidence he sought atonement.
His career flourished, overseas as well as in his homeland, and, in 1957, he was accepted as a member of the British Ornithologists' Union.
Because of its subject matter, this book must have been highly challenging both for Milton to research and to write and for Yorkshire-based firm Pen and Sword to publish.
Even the design of the cover must raised many tricky and unfamiliar questions.
But to everyone’s credit, the project has been processed with utmost restraint and sensitivity.
Perhaps the last word should go to former frontline politician Ed Balls who now works as a broadcaster and, since 2018, has been co-chairman of the Holocaust Memorial Foundation Advisory Board.
In his foreword to the book, he writes: "We should not forget that the crime associated the Holocaust happened across Europe, including on British soil, which is why it is beholden on all of us to remember it as a clear warning for the future so that it is never repeated."
The Birdman of Auschwitz is published by Pen & Sword Books at £25 in hardback
www.pen-and-sword.co.uk
Note: This book is also reviewed at: The Wryneck