‘Twins,’ Jacinta Halloran writes, have ‘a special place in worlds both mythical and real’. This line, in the beautifully poetic prologue of The Science of Appearances, is a small but salient foreshadowing for fraternal twins Mary and Dominic Quinn. Both of them struggle across their lives to find their own special place in the world, and make sense of the myths of family, inheritance and belonging that might constrain or explain precisely who they are.