MacDonald grew up in an unusually literate environment: one of his maternal uncles was a notable Celtic scholar, editor of the "Gaelic Highland Dictionary" and collector of fairy tales and Celtic poetry. His paternal grandfather had supported the publication of an "Ossian" edition, the controversial Celtic text believed by some to have contributed to the starting of European Romanticism. MacDonald's step-uncle was a Shakespeare scholar, and his paternal cousin another Celtic academic. Both his parents were readers, his father harbouring predilections for Newton, Burns, Cowper, Chalmers, Coleridge, and Darwin, to quote a few, while his mother had received a classical education which included multiple languages.