The testament - John Grisham

Troy Phelan, an eccentric elderly billionaire, has written many wills during his life, but right before he dies by suicide, he leaves one final will, a holographic will, as a last surprise. He then leaps from a balcony to his death. He leaves his vast fortune to an illegitimate daughter, Rachel Lane, instead of his six children by three marriages. Her existence comes as a total surprise to everyone. His reason is revulsion over years of fighting with, and embarrassment from, his family, as well as their greed — much of which was due to his neglect of his children and multiple affairs (both personal and business).