When a Gentile decides to have himself circumcised so that he can adopt the religion of his Jewish girlfriend, he explains the dilemma like this: "Either she has to become like me, or I become like her. You really tolerate only your own kind." This is the premise of "The Circumcision", the longest, strangest story in this collection from the author of the critically acclaimed international bestseller The Reader. Indeed, tolerance is a recurring theme in Bernhard Schlink's fiction - and not just tolerance, or the lack of it, between peoples, but the uniquely German issue of how the nation achieves a tolerable assimilation of its collective shame over the Holocaust. If it is true that we tolerate only our own kind - and there is plenty of contemporary and historical evidence - where does that leave a generation who find the actions of their fathers and grandfathers intolerable?
In The Reader, an affair between two Germans - a youth and an older woman haunted by her Nazi past - provided the framework for an affecting study of this intergenerational angst. The couple in "The Circumcision" are close in age, but their love is beset with cultural and racial differences. Andi is a German studying law in New York, whose father was a shady dealer in the booty of the Second World War; Sarah is a computer games designer, an American Jew whose ancestors (those who didn't die at Auschwitz) fled from persecution in eastern Europe. For them, the experience of meeting the parents is more fraught than is usual, evoked by Schlink's incisive prose. Despite all the characteristics that attract them to one another, Andi and Sarah strain under the weight of family, history and their own psychological, emotional and intellectual "otherness". They can't help but pick away at the traits that hint at stereotypes: his Germanness, her Jewishness. Are there innate differences between them that can never be tolerated - or, as Andi comes to believe, that can be resolved only by drastic personal sacrifice?
The notion of guilt passing from one generation to the next also features in the opening story, "Girl with Lizard". A son inherits a painting that he has always loved and, in tracing its origins, he finds it to be hugely valuable. But he makes other, more disturbing discoveries. Did his late father keep the painting, at great personal risk, on behalf of its Jewish owners? Or was he complicit in confiscating it for the Nazis? And how is a young man meant to come to terms with such an inheritance? Again, a set of questions for which there are no simple answers.
Not all of the seven pieces are as subtly executed, and sometimes creaky plotting or thin characterisation spoil an intriguing premise (such as in "The Other Man", about a widower carrying on a correspondence with his late wife's lover, and "Sugar Peas", in which three women exact revenge on a cheating husband).
This is meant to be a book of stories thematically linked by love, and Schlink writes with insight about relationships. But he is more convincing when his lovers' lives are entwined in Germany's peculiar evolution. Here, the cumulative effect - as in Rachel Seiffert's Booker-shortlisted triptych of novellas, The Dark Room - is a compelling composite picture of a nation scrutinising its history. Schlink places his characters, and readers, in a moral maze. He poses questions. The answers, it seems - and this, essentially, is the ethical heart of his work - lie in the necessity to do what is right now.
Martyn Bedford's most recent novel is Black Cat (Penguin, £5.99)