Disguise by Hugo Hamilton

Identity and way people construct a persona to deal with the world is the main theme of this novel. Gregor is a German musician who has constructed a history for himself based on the flimsiest of evidence. He believes that as a small child he was a Jewish refugee who was found during the Second World War and swapped to take the place of a dead German child.
He is convinced that the woman who claims to be his mother lost her own child during a Berlin air raid and was persuaded by her father to replace her real son with the orphaned refugee and say nothing, not even to her husband.
Gregor has no evidence to support this version of his personal history. He has no memory of living with another family or of another mother but the ramblings of an old man who knew his grandfather sow the seed of doubt.
AT 17 he abandons his war-veteran father and mother and travels to England, Ireland, Scotland and around Europe.
He rejects the version of his family history that he knew to that date and constructs a past, based on the words of a man who had been scarred both physically and mentally by the war.
Gregor makes his living as a musician and eventually meets and marries Mara and they have a son, Daniel. Mara and Gregor's friends in Germany accept that he is Jewish - Gregor had himself circumcised when he was an adult but fails to tell his wife this and she thinks it was done when he was a child.
His story starts to come apart when Mara makes contact with Gregor's mother and his marriage breaks up as does his relationship with his son.
The key to sustaining this story is that Gregor has not just made up the story about being a foundling, he believes it and is constantly searching for some dark corner of his memory that would confirm it.
The story is told when Gregor is in his sixties and to some extent has been reconciled with his ex-wife, although less so with his son.
The narrative jumps back and forward in time, blurring fact, half memory and Gregor's assumed version of events.
Author Hugo Hamilton can sustain a mood or create a vignette over several pages in which little happens but which carries the reader through on the back of his lyrical and layered prose.
Gregor may have manufactured a past for himself but it is what defined him as a man and is no less valid than what may or may not have been true.
And there is always the subtext that what Gregor believes to be his past may be the true one.