The idea is that any one who masters some obscenely difficult area can easily be taught anything they are missing. Hell, you can tell them to pick up whatever you need them to know on the weekends. The book and the subject matter I suggested so happen to be brutally difficult. Anything they have to learn at your org will likely be trivial by comparison. Any one who learned this book on their own can easily walk in and out of any math PhD program (let alone other subjects).