The Song of Achilles is a novel by Madeline Miller, first published in 2011. It's a modern retelling of the story of Achilles. It tells the story from the point of view of Patroclus, a prince who's exiled from his kingdom because he accidentally kills his friend. He's taken in by the Phthia Kingdom and meets Achilles, the prince and son of a goddess, a boy who is prophesied to be the greatest warrior of his generation. Even though they're very different from each other, Achilles takes an interest in Patroclus and takes him as his companion. They spend every day together ever since, until the inevitable destiny that awaits Achilles.
If you're interested in Greek mythology but can't tell the difference between Heracles and Hercules or basically just overwhelmed by the complexity of the myth, this book is perfect for you. This book embraces the humanity of characters from Greek mythology through their love, loss, and struggle. It's really easy to follow and even easier to relate to these characters. What makes them similar to us and what makes them special as Gods and mythical entities. If you're already familiar with Greek stories or Achilles' story before, don't be discouraged to check out this book. I think you'll still enjoy it and can find more things to learn about these characters.