From somewhere, back in my youth, heard Prof say, 'Manuel, when faced with a problem you do not understand, do any part of it you do understand, then look at it again.' He had been teaching me something he himself did not understand very well—something in math—but had taught me something far more important, a basic principle.

The Moon is a Harsh Mistress (ed. Hachette UK, 2014) - ISBN: 9781444791044