Sir Ranulph Fiennes on his heroes
28 September 2011 Last updated at 14:02 BST
Explorer Sir Ranulph Fiennes has explained what heroism means to him in his new book, My Heroes: Extraordinary Courage, Exceptional People.
Sir Ranulph became the first man to reach both North and South Poles by land, and the oldest Briton to climb Everest in 2009 at the age of 65.
The book features 12 individuals who he says have inspired him through their extraordinary courage.