Men such as Leonardo da Vinci and Benjamin Franklin used their genius to investigate...http://books.google.com/books/about/Heroes.html?id=e7RXL_lhIBsC&utm_source=gb-gplus-shareHeroesMy libraryHelpAdvanced Book SearchGet print bookNo eBook availableAmazon.comBarnes&Noble.com - $7.55Books-A-MillionIndieBoundFind in a libraryAll sellers ??Get Textbooks on Google PlayRent and save from the world's lar