But "a work of art like this", as the architect in the novel ominously remarks, "demands that the life lived in it be a work of art as well." From the moment when Liesel is deflowered on her honeymoon, and finds the experience "curiously dispiriting" (though she comforts herself that its unromantic aspects are "rather modern"), we know that life is messier than art. Soon, we learn that Viktor is sleeping on his business trips with Kata, a part-time prostitute, and the first of several women in the novel to sacrifice integrity to desperation. Sincerity and honesty are not simple; and nor is love.

This is only one of the triangles of betrayal reflected in the walls of the Glass Room. When the Landauers, and Kata, flee from the advancing German forces, focus shifts to Liesel's friend, Hana - a caustic, tender, bisexually predatory bohemian, simultaneously decadent, barren and life-affirming, who is married but serially unfaithful to a Jew. But the House becomes a clinical laboratory, and Hana takes as her lover a Nazi doctor there who is investigating racial differences. There is a chilling scene in which, after a brutal rape, the doctor wipes the print of Hana's hands off the glass walls, eradicating the human stain.

If the communist love triangle in the last part of the book is less interesting, this is partly because Mawer is the victim of his own imaginative strengths. One is altogether too impatient to discover what happened to the Landauers, Kata and Hana to care about a physiotherapist and her two-timing boyfriend.

And what does happen to them is superbly handled. The Landauers know that they are the lucky ones, though their lives are warped by exile. Others are less lucky. The horrors of a concentration camp are related by a survivor, flatly and retrospectively: Mawer's sympathetic reticence effectively suggests that some things are literally unimaginable.