I was chosen for the mission because: (a) I was in my right mind; (b) I was dispensable and (c) the Minister’s computers decided my skill at crossword puzzles suggested a facility in the processes of analogical thought which might lead me to the Doctor where everyone else had failed. I think the Minister himself thought of me as a kind of ambulant computer. Even so, in spite of the encouraging voice with which he wished me farewell, I guessed it was something of a forlorn hope.
