The song of names : a novel / Norman Lebrecht.

Enhanced descriptions from Syndetics:

Martin Simmonds' father tells him, "Never trust a musician when he speaks about love." The advice comes too late. Martin already loves Dovidl Rapoport, an eerily gifted Polish violin prodigy whose parents left him in the Simmonds's care before they perished in the Holocaust. For a time the two boys are closer than brothers. But on the day he is to make his official debut, Dovidl disappears. Only 40 years later does Martin get his first clue about what happened to him.

In this ravishing novel of music and suspense, Norman Lebrecht unravels the strands of love, envy and exploitation that knot geniuses to their admirers. In doing so he also evokes the fragile bubble of Jewish life in prewar London; the fearful carnival of the Blitz, and the gray new world that emerged from its ashes. Bristling with ideas, lambent with feeling, The Song of Names is a masterful work of the imagination.