He is an extraordinarily intelligent man. At the age of
twenty-one he was a professor of mathematics. For
years he was one of the most important men in the
world of mathematics. Then he disappeared from
university life. Soon after that I began to realize that
crime in London was changing. Someone was telling
criminals - who are usually stupid and uninteresting
little men - what to do. They were obeying the orders
of a mastermind. It could only be Moriarty. But I
could never catch him. I hate his crimes, but I
recognize his intelligence. He is the only criminal who
interests me, because he is the only criminal who is as
intelligent as I am.