P. D. James 
Part-Time Job [EPUB ebook] 

My only regret is that I shan’t be alive to savour my retrospective triumph. But that is of small account. I savour it every day of my life. I shall have done the one thing I resolved to do when I was twelve years old – and the world will know it. Follow the ‘Queen of Crime’ as she takes us into the mind of a man who has waited decades to enact his patient, ingenious revenge on a school bully.