This was on my parents' bookshelf for as long as I can remember and my dad mentioned it several times as one of his favorites. It's about a group of english children who get kidnapped by pirates when leaving Jamaica for England sometime around the turn of the century. It's an amazing book, all told from the voice of an adult who sees things the way the children do. It has a similar tone to some of the english children's adventure books like Box of Delights or Swallows and Amazons but you as the reader can tell the whole thing is totally grounded in reality. It's the way the kids see the world that makes it all so fantastic and dreamlike.
There is also an interesting critique of colonialism and the wavering moral certitude of the British Empire just after its peak. I really don't want to say too much about what happens in the book because a lot of the pleasure is in just experiencing the narrative for yourself. Strongly recommended. A quick read that will take you far from yourself.