Well, the first War of the Machines seems to be drawing to its final inconclusive chapter — leaving, alas, everyone the poorer, many bereaved or maimed and millions dead, and only one thing triumphant: the Machines. As the servants of the Machine are becoming a privileged class, the Machines are going to be enormously more powerful. What's their next move?

Letter to his son, Christopher (30 January 1945); published in The Letters of J.R.R. Tolkien (1981), Letter 96