Treehouse Books & Melanie Voland 
Odysseus Meets The Sirens and Other Gods and Monsters: Traditional Mermaid Folk Stories Collection [EPUB ebook] 

This is a short story version of the ancient Greek mythology epic poem, ‘The Odyssey’ by Homer, which describes the adventures of a Greek warrior and king, on his ocean voyage home from the Trojan war, that should also be a lot easier to understand, and is centered more around Odysseus’ meeting with the Sirens and other ocean monsters.
The story itself still contains a level of violence, that would make this book unsuitable for younger children. Though anyone else can read it.