Erskine Childers 
Riddle of the Sands Level 5 Oxford Bookworms Library [EPUB ebook] 

A level 5 Oxford Bookworms Library graded reader. Retold for Learners of English by Peter Hawkins. When Carruthers joins his friend Arthur Davies on his yacht Dulcibella, he is expecting a pleasant sailing holiday in the Baltic Sea. But the holiday turns into an adventure of a different kind. He and Davies soon find themselves sailing in the stormy waters of the North Sea, exploring the channels and sandbanks around the German Frisian Islands, and looking for a secret a secret that could mean great danger for England. Erskine Childers novel, published in 1903, was the first great modern spy story, and is still as exciting to read today as it was a hundred years ago.