Steve Irwin's father is revealing a touching tribute his son tucked away 12 years before his unexpected 2006 death. Bob Irwin shared the letter for the first time in The Last Crocodile Hunter: A Father and Son Legacy, which he penned to commemorate the 10th anniversary of his son's death. Irwin wrote the note in 1998, telling his parents: "Probably one of the most unfortunate things in a 'Bloke's Life' is that it takes over 30 years to realise how essential you have been to build my character, my ethics and, most importantly, my Happiness." He continued, "At 32, I am finally starting to figure it out.