I began this novel, set in Germany between the two world wars, after watching the film Valkyrie. I found the film both shallow and grandiose, dominated by clicking heels and clashing chords; the choice of Tom Cruise to play Claus von Stauffenberg was singularly inept. Cruise is a Hollywood celebrity; the personality of von Stauffenberg, aristocrat, soldier and man of great personal charisma, with a deep love of his country and a foreboding about the direction it was being led by the Nazi Party, vanished inside the heroics.

However, the novel returned me to the real world, one that would have been familiar to von Stauffenberg, who was born in 1907 into the Catholic nobility of South Germany and who contemplated a career in music before deciding to join his family’s regiment. Lucy Beckett places her story in the Silesian countryside and in Breslau. Her main character is Max von Hofmannswaldau, half-Jewish, half-Protestant, born in 1905 and raised on a Silesian country estate until he leaves for the Breslau Gymnasium to continue his studies. Here he makes friends with Adam, Count Zapolski, a Pole and lapsed Catholic, and comes under the benign influence of the classics master, Dr Alois Fischer.

Later, at Breslau University, the two young men, now studying law, include Joachim von Treuburg, the son of an East Prussian Junker, in their circle. Von Treuburg is studying medicine and he introduces his friends to a fellow medical student, Jacob Halperin, a Jew from Vilna, and his sister Anna. Music is intrinsic to their lives. Max and Jacob play the violin, Joachim the cello and Ann, the viola; a quartet is formed. Later, as the political situation in Germany darkens and the students struggle between the prejudices of their background and their own idealistic instincts, it provides a common language; "If music can’t break down the walls of suspicion, what can?"

Max had imbibed the music of Bach and the related values of "faith, patience, hard work" at the hands of his childhood tutor, Dr Mendel, a Jew. Later, he is exposed to Wagner’s music and recognises with disquiet its direct assault on his senses. The spectre of Nietzsche, who had famously proclaimed "God is dead", also haunts this unstable German society. As Beckett reminds us, "If God is dead, he has never been alive." God had not died, despite the Nazi wish to entomb him, yet the forces of evil will have their day: Mendel commits suicide and nemesis will also overtake the group of serious-minded companions. Adam returns to his faith in Poland, to be tortured and killed by the Russians. Treuburg (as with von Stauffenberg in real life) was executed by the SS in 1944 for his suspected part in the July Plot. Jacob Halperin, now a doctor and soldier in the Polish army, is shot in Katyn Forest and his sister is murdered by the SS in Lithuania. Only Max survives, with the painful burden of his memories; he flees to England in 1933, when Hitler becomes Chancellor, to earn his living as a private tutor and violin teacher.

The book is essentially a novel of ideas, developing in fictional form what Lucy Beckett explored in depth in her study of Western literature, In the Light of Christ. All the questions she raises in that earlier work concerning the relationship between Christianity and culture are here given urgent practical application. Goethe, whose spirit was meant to inform the fledgling Weimar Republic created in the chaotic aftermath of WWI, had believed that "he who possesses art and science has religion." As the 1920s unravel, the thuggish Brownshirts increase in influence, the Centre Party weakens, anti-Semitism grows and the Nazis and Communists struggle for power, the inescapable conclusion is that "Culture instead of God... it hasn’t worked."

Max describes Berlin to Adam as "Sex, whisky and money". This is the artistic decadence conjured up by Christopher Isherwood and the film Cabaret. The moral collapse of the German middle classes is also known from memoirs such as The Himmler Brothers. Himmler’s father had been head of the Wittelsbacher Gymnasium in Munich and was, like Dr Fischer, a classical scholar. Unlike Beckett’s schoolmaster, he became an enthusiastic Nazi – as did so many German Catholics, believing Fascism preferable to Communism. Beckett chooses to situate her novel within an aristocratic elite. Why? Perhaps because their ancient, privileged status allows her to discuss the sacrificial qualities of true leadership. Dr Fischer tells his class, "If democratic government is to work in Germany, we must have good people who are also clever and brave, to take responsibility."

The author’s grasp of the intricacies of German politics is masterly. The novel opens in 1914; the wounds caused by the Great War fester throughout the years that ensue. Beckett makes a good case for why the army commanders followed Hitler’s military folly for so long; Max’s father tells his son that "the Prussian nobility will never, never accept [the Treaty of Versailles], nor will the Prussian army." His brother, Heinrich, shocks him by joining the SS officer corps. Max wonders, "Could this be what Prussian military honour and obedience had become?"

The most interesting character in the book is Adam, Max’s friend, who constantly argues against belief in God in Dr Fischer’s classes. Affecting a youthful cynicism, he dominates the less worldly Max with his wider reading, his musical gifts and his charm. Returning to Cracow, he happens to hear a sermon by the (real-life) Archbishop Sapieha; in a dramatic volte face, he becomes a priest. Faced by the false ‘religion’ of the Nazis, he chooses Christ alone.

Through her vivid evocation of the doomed lives of a group of high-minded, highly educated young people, Beckett’s novel charts the collapse of a whole civilisation. It raises questions of enduring importance. At its conclusion I felt acute sadness for the loss of a generation, both real and imagined.