BR thanks Hilton warmly for her book Logic, Computing Machines and Automation, of which he has only read parts, but finds those parts very interesting. "In particular, I am grateful for the nice things you say about Principia Mathematica and about me. The followers of Gödel had almost persuaded me that the twenty man-years spent on the Principia had been wasted and that the book had better be forgotten. It is a comfort to find that you do not take this view."