"Treasure Island" by Robert Louis Stevenson
I read this book when I was a child, which was a few years ago, and loved it then. And I still loved it now! If you like pirates, sea voyages, adventure and a mystery you will love this book.
It all starts when a seaman comes to the 'Admiral Benbow' inn. The seaman brought with him his sea chest and the contents unknown at the time by anyone. Jim Hawkins is the boy in this story and he is telling the story. After some time the seaman has some visitors that want his sea chest and what is in it. He gives Jim the message that if anything happens to him to take his sea chest. Some men (pirates) come for the seaman and he is killed. Jim gets the sea chest and it's contents and takes it to Dr. Livesey and Squire Trelawney. They open it and find a map of an island. This starts the adventure to Treasure Island.
Wonderful classic book that I personally think every child should read!