" It's a piece of cake, being a lawyer or a doctor or a computer systems analyst or an accountant. Libraries are full of books telling you how to do it. The only textbooks for private eyes are on fiction shelves, and I don't remember ever reading one that told me how to interrogate an eight-year old without feeling like I was auditioning for the Gestapo. "

― Val McDermid , Crack Down (Kate Brannigan, #3)