The Madingley paper56 represented a kind of closure for me, a climax to the first part of my scientific career, beginning in my early twenties and ending in my early thirties. At this point, I took off in an entirely new direction, never to return to those youthful mathematical pastures. That new direction, which was to define the rest of my career, and approximately the second half of my life, opened up with the publication of my first book, The Selfish Gene.