Fallada's novel, scribbled in 24 days, is nonetheless neither raw nor inchoate, but reads as if molten emotions have been obsessively pounded into hard shape.

The Glass Room, by contrast, is delicately subtle - an affair of shifts and shades, retrospective ironies and elegiac grace-notes. Again, the book is constructed around a kernel of truth, though the true-life core of this book is a house, not a hero. The glass room in the novel is in the Landauer House, a modernist masterpiece near a provincial Czech town, with an extraordinary wall of translucent onyx. The original is evidently Villa Tugendhat in Brno, built by Ludwig Mies van de Rohe.

"Architecture", Mies declared, "is the will of the epoch translated into space"; and this is the theme of The Glass Room. The spaces of the Landauer Hous - built as a shrine to a modern marriage, but becoming a Nazi laboratory and then a communist clinical gymnasium - witness the epochs of Czech history. This sounds desperately pretentious. Against all expectations, however, Mawer has created a novel that is subtly and movingly human rather than ponderously symbolic.

This is because in Mawer's novel the symbols are shifting, perceived and projected by the changing cast of characters that pass through it. For the young couple who built the House, the Jewish car manufacturer Viktor Landauer and his gentile wife, Liesel, it is a symbol of their thoroughly - perhaps dangerously - modern marriage. Like John Donne, proclaiming that writing his name on glass is a symbol of "all-confessing and through-shine" love, the Landauers see their Glass Room as a shrine to luminously modern personal honesty - and also to "a dream that went with the spirit of the brand new country in which they found themselves, a state in which being Czech or German or Jew would not matter, in which democracy would prevail and art and science would combine to bring happiness to all people."